Thanks chaps, then this looks to be a made up of a bit of mix up of parts as this one doesn't have 'super' on the cylinder.
Ah well, a tiny bit of work and it'll shoot, so still good for £15
EDIT:
Hmm, the plot thickens, this does seem to have a 'chunkier' style stock. I'll post a pic up in a few minutes so that you chaps can look for yourselves.