Hi oboran and welcome to rootschat
I have put a link to the post you are referring to but as Reid and variants are so common in this country it might be better to do a bit more research on your John.
Do you have the 1871 census? If so can you quote the reference? I have found one John of the right age in Bury but he is shown as born in Kent and is not running a shop. His occupation simply says "Pension" which may be an army one I suppose.
Regards
Andrea