aHAVING your picture taken for the paper is

an ordeal most playwrights see as an embarrassing chore. Not so Sharman Macdonald. When she arrives at the Tron Theatre, bags in hand, straight off the train from London, only to be met by The Herald photographer, she hardly hesitates before whipping off her coat, and stepping out into the damp evening to pose beside the gates and glass of the Glasgow theatre's newly built box office. Of course, it's not the first photo-shoot the author of The Winter Guest, and When I was a Girl I Used to Scream and Shout has had to endure, but there must be something of the performer still in the former actress for her to rise so readily to the task.

Acting, she says, is something she no longer desires to do. After Edinburgh University, the Glasgow-born Macdonald moved to London (for love, she says, not money), and secured acting roles in several new plays. These were her grounding when she put acting behind her, and turned to writing.

Three times she was offered a part in the internationally successful When I was a Girl I Used to Scream and Shout, the West End hit that made her name in 1984, and each time she declined. But watch her light up as she talks about her 13-year-old daughter's nascent acting career (parts in the recent Coming Home on BBC1, and the forthcoming Star Wars movie), and you'll see that her old love of performing has yet to fade.

She's in Scotland for a couple of reasons. First, to do preliminary research on a Glasgow-based screenplay, and second, to be around for the stage premiere of Sea Urchins. Written for radio, and broadcast on Radio 3 and 4, Sea Urchins is being brought to the stage for the first time by the Tron's artistic director, Irina Brown, in a co-production with Dundee Rep.

Shockingly, this will be the first time a Scottish company has premiered one of Macdonald's plays.

It's true that Edinburgh's Royal Lyceum was the first theatre to welcome When I Was a Girl . . . after its London debut, but it is equally true that the old Traverse had failed even to read the script. Perth Theatre's recent production of her 1989 play, When We Were Women, was a reminder that Macdonald has had her misses as well as her hits, but that doesn't account for why so little of her work has been seen here.

Macdonald is not bitter about being neglected in her homeland - it's a long time since she's lived here, after all - but however much she has grown to like London, there's a part of her imagination that is forever Scottish.

''I love the fact that Sea Urchins is going on up here, but it does have only two Scottish characters in it,'' she says about this rites-of-passage tale set on the Welsh coast circa 1961.

''I've longed to come back, and for a play to be first produced in Scotland, but I'm also just grateful that they get put on anywhere. There are so many good writers around, and you go where you can.

''There is an audience in my head in my office when I'm writing who don't receive things in a quiet fashion, and they misbehave when they don't like what they hear. I write for that dialogueing audience, but I don't mind who they are.''

She adds: ''I've written one play with five English boys and two Scottish girls that was set in Devon, but largely I do write in the Scottish tongue. There's less dialect than there used to be, but it still has a cadence.

''Even when I'm writing Australian, which I am at the moment, I use the cadence and the rhythms of Scottish language to feed into it.''

This is a productive time for the 47-year-old writer. As well as Sea Urchins, and her screenplay idea, she's working on the script for a two-film British-Australian television co-production, and a play for young people.

June will herald her debut as a librettist, having written the words for Hey Persephone, an opera set in Glasgow, scored by Deirdre Gribbin, and due to be performed at the Aldeburgh Festival. The Winter Guest, starring Emma Thompson and Phyllida Law, is released on video next week.

Film-writing happens to be foremost in her mind, but she likes to keep options open.

''Beware of definitions,'' she says. ''If somebody asks me to do something, and there's a spark between us, then I will try and do it. I'd never have written an opera unless someone had asked me. And I do not think of myself as a librettist - I can say that categorically!

I wouldn't have written the radio play, and I wouldn't have done the screenplay of The Winter Guest, if I hadn't been asked. It was something to do with being completely broke and having to sell the car in order to pay a tax bill, but not wholly to do with that. It was a feeling that maybe I had more places to go.''

Theatre is where she feels the most free, least prone to censorship, and most connected to the audience. ''I'm very fond of Sea Urchins, and I hoped that it would have more life,'' she says, agreeing that even winning Sony Awards, and attracting large audiences, radio plays never have the impact of theatrical productions.

Faber is publishing the script of Sea Urchins now it's a stage play, even though many more people heard the radio version. ''I'd much rather a play had a theatrical run, even if it attracted only one person a night. If it's there for three weeks, it exists. I'm very lucky that Irina Brown heard the play and wanted to do it on stage.''

n Sea Urchins is previewed on Saturday May 16 and Tuesday May 19 at Dundee Rep, then runs May 20 - June 6. It plays the Tron Theatre, Glasgow, June 17- - July 11. Hey Persephone is at the Aldeburgh Festival, Suffolk, on June 26.