Pinkgirl - I'm assuming that was sarcasm as Martin compston is in fact scots? Ah and I see you were!
There's quite a few scots actors who use English or much softer scots accents for their acting work. Sometimes even American accents.
Ewan mcgregor
Gerard butler
Richard Wilson
Laurie Brett (as already mentioned)
David McCallum
Annette crosbie
Phyllis Logan
Ellie Haddington
Hannah Gordon
Gordon Jackson...
I have a 'forces accent' which is a mish mash of scots (which I am, born here scots parents), various English counties, welsh and tinged of Dutch and German. All places I've lived.
As well as bidialectalism there's 'accommodating' where you slip into the accent of who you're talking to, or a strong accent you've been listening to. My dd picks me up on it if I've been watching an Australian show or one with a presenter with a strong accent or been speaking to family or friends with clear accents. Don't know I'm doing it, it's a subconscious act believed to be with the aim of being understood/accepted within a community.
It's REALLY hard to get back to my 'normal' voice.
If I'm drunk or tired I'll also sound more scots. I did live in Scotland for 7 years as a child but not all in one go.
As this thread shows it's very common. If she is genuinely a friend why does it bother you?
"It depends who is listening" I'm so stealing that next time someone takes the piss!
I do like having fun with people who ask where I'm from - as they'd never guess from my accent! Plus I'm back living nearby and they assume I'm not from here - taxi drivers don't get away with taking me the long route 