There are London businesses that will not even accept Scottish
currency, although I suspect that they a legally obliged to do so.

There have been times when I have refused to pay with anything else,
having no English money about my person.

We see a lot of Scottish money, here in the Lakes, but I'm fairly sure it
isn't legal tender.

I was in a pub in Portsmouth last weekend, and the guy in front of me was
offerred a Scottish £5 in his change - and refused to accept it. When I was
served, I too had the same offer, and took the note.

Half an hour or so later, when I went back to the bar, I simply handed it to
a (different) member of staff, who looked at it oddly for a brief moment,
then stuck it in the till.

That said, I've had a few RBoS £1 notes in the recent past, which a UK shop
refused to accept - I simply exchanged it at the nearest bank for a small,
gold-ish coloured coin, with no questions asked by the teller.

Matt