Thanks Craig380, that's another really helpful response! I definitely feel a lot more confident buying a used bike on my own than I did a few days ago.
I have called a few dealers and given my price range (£1.5k-2k) they have said I am unlikely to be able to get one from them as they wouldn't take bikes that old. So it looks like a private sale is my only option at the moment.
My hunt continues, I will keep you updated and if anyone local does see this, feel free to say hi