Coleford Baptist, which burial ground would I find his grave?

I would imagine the graves would be in the same grounds as the Chapel.

Here are a couple of web pages about the Coleford Baptist which give you contact details so you can find out for certain.

http://colefordbaptists.org/
http://www.eden.co.uk/churches/coleford/coleford_baptist_church_10086.html