Thank you, I have been doing my nut in trying to find out what it is, I was wondering if it was a 1 or a 7 so I am now going to keep with this, its 1981 Worksop frame.......are you definite its 1981?
Possibly the frame builders number, I know for a fact that Mercian did that as a chap walked up to my Mercian, up-ended it and told me it was built by frame builder number 7 - and he was frame builder number 10!
No idea if the Worksop builders used the same system though.