Sadly I finally got all the muck and grease off to find that the rest of the frame number had been ground off!
I guess that makes it unuseable for a restoration project.

Thank you for the info Roger.
Finally managed to get all the grime off and found the frame number. You are correct, I believe, in that it is a C10 frame, although the number starts with DC10s, not sure what that makes it?

I have acquired a frame which I have been led to believe is from an Ariel Colt, I have had a search around for a frame number but can't seem to find one. Would it be in the 'usual' place around the headstock or did they put them somewhere different?
Any suggestions welcome

Thanks