TOMMY Sheppard is used to being busy in July. There are always acts to book, venues to prepare, tickets to sell. Sheppard still bears traces of his life as impresario at the Stand Comedy Club – polka dot tie, unkempt thatch of spiky hair – but nowadays it is the business of Parliament, not the upcoming Edinburgh Fringe, that has him run ragged.

“It’s like a combination of working in a museum and being in the cast of a pantomime," says the MP for Edinburgh East when we meet, in Westminster Central Lobby. "The only way to get by is by taking on an air of irreverence.” The setting feels like a BBC period drama: marble floors, light streaming in through stained glass windows, a plethora of stern-looking statues. Outside, tourists with cameras around their necks queue for the chance to nose around “the oldest parliament in the world” ™.

“This place has been designed to make working-class people feel six inches high,” says Sheppard as he talks me through the seemingly labyrinthine parliamentary etiquette. Red denotes the Lords, green the Commons.

With a mischievous glint in his eye, Sheppard leads me down a narrow corridor bedecked with red carpet, and up a flight of stairs into the viewing gallery overlooking the Lords. Below us, rows of peers sit, some a good deal more animated than others. “All of them unelected,” Sheppard says with a theatrical sweep of his arm.

Afterwards, Sheppard, pictured right, takes me across the hall to the Commons. It is my first time in the debating chamber. I’m struck by how overblown and anachronistic it all seems, like the oversized bearskin hats on the Queen’s Guard. The chamber itself is wee, much smaller than Holyrood.

“It’s not much bigger than Hackney council,” says Sheppard of the north London administration of which he was a

Labour deputy leader 25 years ago. But where Hackney council sat a few days a month, the Commons is open for business for more than 30 hours a week, passing legislation that affects every corner of the United Kingdom.

This is the world that Sheppard and 49 of his new SNP colleagues have been getting to grips with over the last two months.

“Our purpose here is two-fold,” he says. “One is to provide effective representation for Scottish interests across the UK. The second thing is that as long as we remain part of the United Kingdom, we would like to play a role in changing it.”

Last July, Sheppard was combining the build-up to the Edinburgh Fringe with campaigning for independence. Although he says he could not have imagined himself an MP then – or even an SNP member – he has adapted well to Westminster, negotiating the quagmire of parliamentary procedure to good effect.

He is a frequent visitor to the House of Commons library (“You ask them any question under the sun and they’ll help you”) and sits on the Standards Committee. First order of business? The investigation into Alistair Carmichael.

The baptism into parliamentary life has not been easy. In the chamber, none of the numerous SNP amendments to the Scotland Bill were adopted. Outside it, there was the small matter of effectively swapping lives overnight.

“We were down here on the Monday after the election with nowhere to live, no job description and not sure what we would do with such a huge mandate," says Sheppard. "We had to acclimatise really quickly.”

That acclimatisation included finding somewhere to live. An MPs’ £400-a-week housing allowance would cover a palace in most of Scotland, but does not go far in London – as Sheppard discovered.

“I was looking at basement student flats. I thought ‘I’m 56, I can’t be doing this’.”

As well as settling into a new flat and a new job, a fair few of “The 56” had to get to know each other, too. “At the point of the election I might have known half of the group. We have all got to know each other really quick,” says Sheppard. “We are still getting to know each other.”

The surprising sociability of Westminster life – the place is so small it seems impossible to avoid running into people – makes that task a bit easier. As we linger outside the entrance to the Commons, a flurry of SNP MPs wander past. There is old-stager Pete Wishart, and fresh-faced Aberdeen South MP Callum McCaig. It feels more like an anteroom at an SNP party conference than a Westminster lobby.

Last time I met Brendan O’Hara, right, he was wearing jeans and a T-shirt in a hipster cafe around the corner from my flat in Glasgow. It was raining outside. Four months later we are sitting drinking tea on the terrace overlooking the Thames. The London Eye gleams in the bright summer sun. At the table behind us, Conservative London Mayor hopeful Zac Goldsmith sits surrounded by sharp-suited apparatchiks. We are definitely not in Partick now.

O’Hara has lost none of the charm and openness that I encountered before he was elected MP for Argyll and Bute. When I ask about the most surprising aspect of life in Westminster he is disarmingly frank.

“It’s incredibly busy. I never thought it would be this busy,” he says. “You haven’t changed jobs, you’ve changed lives. This is genuinely life-changing.”

O’Hara recalls the day he arrived in London, on that famous flight from Glasgow with 12 other freshly elected MPs. “It was pandemonium, TV cameras everywhere. Then Mhairi turned up. They all went nuts for Mhairi.”

The media circus that surrounded the SNP in that first week has fizzled out – although it was briefly rekindled last week by Mhairi Black’s maiden speech. Meanwhile, O’Hara and the rest of his colleagues have had to learn the business of parliament, which can at times be prosaic.

“You start and you think, ‘I will never get to grips with this’. This tsunami of information crashes into you and you are lucky if five per cent sticks. But it’s remarkable how you come to grips and understand things.”

Alex Salmond, back in the House after a hiatus as Scotland’s First Minister, has been a big help, says O’Hara. “Every single one of us has looked to him for a lead – [though] he doesn’t act like the leader. He doesn’t seek to undermine Angus [Robertson] in any shape or form but for us newbies he has been fantastic.”

Perhaps Salmond sees something of himself in the one-time TV journalist. O’Hara has been one of the most impressive of the new SNP intake, particularly on Trident. He is the front-bench spokesperson on defence. But he admits that becoming a parliamentarian is a strain, too. Throughout the referendum and then his successful election campaign, he worked alongside his wife, Catherine, and two daughters.

Now the O’Hara family is in Helensburgh while the pater familias spends four days a week in London. “We were in it together. We were a unit. Then suddenly it is just me,” he says. “Suddenly the people who mean most to you in the world are going, ‘How do we fit into this?’”

At Westminster, O’Hara has been “shocked” by the lack of understanding of Scottish affairs among his fellow MPs, but “on a personal level some of them are actually very nice.” Is there any danger, as some forecast, of some SNP MPs going native? Might the allure of lunches on the terrace and the pomp and ceremony of Westminster prove too great?

O’Hara, who wears Yes cufflinks, rejects the idea. “Nonsense. It is our politics that sets us apart,” he says. As if on cue, a bagpiper starts up on Westminster Bridge.

There is clearly a strong bond between the SNP group. As we speak, Ian Blackford, MP for Ross, Skye, and Lochaber stops by for a quick chat. He is carrying an armful of papers and accompanied by visiting friends.

The previous week, O’Hara’s family sat on the terrace with Mhairi Black taking selfies. “You come out here and it could be any one of the 56 and you just sit down and start chatting,” he says.

Barely two months have passed since the May 7 earthquake, and yet so much has happened. The Scotland Bill, English Votes for English Laws, fox hunting. I notice the expiry date on O’Hara’s Westminster ID: 05/20. I can’t help but wonder how much will have changed by the next General Election, and how much life here will have changed the SNP and its new parliamentarians.

Westminster itself is badly in need of renovation, to the tune of at least £3 billion. The whole place has the feel of Alec Guinness-era Tinker, Tailor, Soldier, Spy: lots of rabbit-warren corridors, clandestine meetings and an unmistakable whiff of faded glamour. At the same time, however, there is power behind the fusty procedures.

“There are so many rules and conventions that you don’t even know what you don’t know,” says Natalie McGarry, right, MP for Glasgow East. “It is a learning curve every single day. It is a bit like moving from primary school to high school.”

At times, SNP MPs have been forced to bend to the will of Westminster’s diktats. The clapping and cheering in the chamber has largely ended, after warnings that speaking privileges would suffer if it continued. Keeping up the wave of hope that swept the party to victory in May amid the daily grind could prove difficult. “You are ground down,” admits McGarry.

With a Tory majority government in power, the room for manoeuvre is severely limited. “It is tough when you’re one of the poorest constituencies in the country, where people are already on their knees,” she says. “But at least us being here as SNP shows how unbalanced the relationship is between Scotland and the rest of the UK.”

The sun has moved over the Houses of Parliament, casting the terrace into shade. It is Thursday afternoon, time for the weekly exodus of SNP MPs back north to their constituencies. There is talk of travel arrangements, of sharing taxis and trains.

McGarry is going back to Glasgow for the weekend too, but is particularly looking forward to the parliamentary recess, which begins this week. “I can’t wait to get into the constituency work," she says. Any chance of a holiday? “I don’t know.” She shakes her head in a manner that says “nae chance.”