13-07-2021, 04:37 PM
The piston could be Seven Workshop but it could be something older. Hepolite, Wellworthy etc. Look inside and there should be a manufacturer's name or a reference number (SW if Seven Workshop) on the side or underside. Replacing one piston in isolation is something I'd not do but I have a few odd pistons I use for sizing bores (not sure I've a SW +60 though) and if that's what you want to do I'll look to see if I've a match.
Steve
Steve