Thanks northern power. I will look very critically and take photos, my mechanic friend now knows what to look for thanks to your advice and that of the others that have been kind enough to post.
My concern is that with so few in Scotland I can't take my mate down south if I find one I like so I need to be able to suss out problems myself too
You do need to be able to sort out problems yourself but if there is one where your mechanic can't get to you could always post on here and if you gave sufficient notice there may be a knowledgeable local member who would look at it with you.