Thanks for the info. Looking at the piccies I think it is a '93, I will check the Shimano date once it stops raining! I have fired a mail to Dawes to see if they can shed any light on the manufacture date, if I get a response I will post up.
I have to say that aside from the dent in the top tube it is almost 'as new', I may stick the mudguards back on and take a couple of piccies and conduct a straw poll - with or without and let the experts decide!
Re the seat hight, I took the piccie before adjusting the bike to ride it - the frame is probably a couple of inches bigger than I would buy now, but it is still an incredibly comfy ride.
I went for a quick 20-miler last night and took in the Great Park in Windsor, in the dark. Half way through the park I was stopped by the Royal Police who pointed out I should not be in the park after dark - ticking off and formalities over with, he then commented on how nice the bike was and asked where he could get one!