After doing some digging around, It's definately not a Rossin. It's more likely to be a Brian Rourke.



Looks very similar to the wrapover steat stays of Rourke frames, like this one here :-

http://www.flickr.com/photos/60987663@N00/53863504/

I've sent Rourke's an email. I think i'll be more chuffed if it is a Rourke. They're a local builder, and I can pop 30 miles down the road to get the frame sorted