MUSIC at Paxton has just doubled in size. I’m not talking number of concerts or days or audience or ticket prices – that’s all still as bijoux and snug and reasonable as ever. This summer’s programme features, rather impressively, pianist Angela Hewitt playing Bach and Scarlatti, violinist Alina Ibragimova playing three concerts including an all-Beethoven recital featuring the Spring Sonata and the Archduke Trio, Pieter Wispelwey playing Bach’s cello suites, and violinist Rachel Podger playing Mozart. Any one of those concerts would sell well at major UK concert halls, but Music at Paxton is never going to be about mass entertainment, not when its main stage is an ornate picture gallery nestled within a neo-Palladian mansion on a B-road in the Borders that seats 140, max.

What has grown two-fold is the festival office, upped from a grand total of one staff to two. And the new general manager is a plain-speaking Yorkshirewoman whose unstuffiness and pragmatism might just be what’s needed to open up access to this tiny gem of a Scottish summer series.

It takes a certain character to be an excellent festival management: a fine balance of passionate and personable, supremely sensible and unflappable. Oh, and you can’t be a glory hunter.

“There’s a very different sense of satisfaction you get from being behind the scenes than what you get from being on the platform,” says Elizabeth Macdonald, new manager of Music at Paxton and a woman who says she loves working behind the scenes with the kind of matter-of-fact zeal that makes me genuinely believe her. “When a concert goes well, it is just as exciting knowing you’ve been part of making it happen.”

Macdonald comes from a background where classical music was normal and inclusive and fun. She grew up in Hull, both of her parents musicians (father a harpsichordist and lecturer at Hull University “for donkeys years”, mother head of music at a local comprehensive). She tells me about sneaking out of school aged 11 to go to a lunchtime concert with her dad – it was the first time she’d heard Schoenberg’s Verklärte Nacht, and it “absolutely knocked me sideways”. Her father also conducted the Hull Bach Choir, which she joined to sing Monteverdi’s Vespers aged 10. As soon as the kids were old enough they “started bashing through trio sonatas” of a Sunday afternoon. It all sounds very Mendelssohn-on-Humber.

But what’s lovely about listening to Macdonald speak about her childhood is how totally un-rarified it clearly was. When she comes to talking about ticket prices and widening local audience access, and says that these are important issues for her because she comes from a poor city, it’s obvious that she’s not just rehearsing the politically-correct catchwords required of a festival manager.

She became a violist, moved to Edinburgh to study music and set up a string quartet with a friend. Meanwhile she cut her admin teeth organising university string orchestras and early music ensembles, and after she graduated the freelance work ramped up: concert manager for Edinburgh International Festival one summer, administrator for the Georgian Concert Society for a spell. She was biding her time for the right job to come up, something she could sink her teeth into.

Then last year it came up in the Borders. Paxton is only just in Scotland: a two-minute swim across the Tweed and you’d be in England. (Intriguingly, Paxton audiences tend to travel from Edinburgh more than they do from Newcastle though the two cities are equidistant; “maybe that river is a psychological barrier,” Macdonald says.) The house itself is opulent inside and out, an Adam stately home built in the 1760s, stuffed with fine things to look at. It holds one of the best collections of Chippendale and William Trotter furniture in the UK, and of course that Regency Picture Gallery hung with Raeburns, Wilkies, Hunters and Peploes, on loan from the National Galleries of Scotland.

“Paxton really is hidden gold,” says Macdonald. “It’s off the main road so you could miss it, but that’s part of its charm. The main beauty of the festival is how intimate it is. The Picture Gallery is a stunning place to hear music: you are so close to what’s happening on stage, which heightens everything, makes everything seem more intense.” She acknowledges that some people come to the festival mainly for the paintings, because being at a concert is a fine way to spend a significant amount of time in the company of those Raeburns and Scottish Colourists.

How does such a miniature stage manage to book the Hewitts, the Ibragimovas, the international stars?

“Well, Alina first came to us in 2009 when she was really young. We’ve found that if we get people when they’re just on the cusp, before they get their big status, then they tend to love the atmosphere and want to come back.” Hardly surprising, then, that those 140 tickets get snapped up.

“And audiences also get to know each other,” Macdonald adds. “People who come regularly know that they’re onto something special so they come back every day of the festival, and there’s a real sense of a little community here.”

Which all comes across as terribly lovely for those in the know, a bit less lovely for those on the outside. Is it possible to get away from the image of a posh house with its audience of privileged insiders? One point to make is that the highest ticket price is £25 – that’s for Angela Hewitt’s recital – and Macdonald says she’s looking at ways of bringing prices down elsewhere.

“And actually, I’m not sure we need to get away from that image entirely. Paxton is what it is, and there’s no point in pretending otherwise. It is a privilege for anyone to hear these artists in this environment, so the key thing is extending that privilege.”

She takes a breath, knowing she’s wading into deep water. But wade she does. “Through the year the house tries to be as open and welcoming as possible. If people are locals, then Paxton is part of them and they are part of it.”

She tells me about a phone call she received that morning from a couple in Berwick Upon Tweed asking if they could bring their young children to one of the taster concerts – taster concerts being a free Sunday afternoon series held in the picture gallery before the festival proper.

She assured the couple that they should absolutely bring the kids. “If they get bored, they can leave, and there’s a very nice playground in the grounds. Anyway, a bit of background noise during a concert can add to the live experience. If you want a sterile environment, go listen to a CD at home.”

Music at Paxton runs July 15-24 at Paxton House near Berwick-Upon-Tweed