John Bence's parents were:
James Bence - bap 11 Aug 1754 West Kington, Wiltshire d 5 May 1814
Mary Tanner - bap 25 Aug 1754 Kelston, Somerset d 28 May 1813
Married 4 Nov 1783 Kelston, Somerset
freereg is a website - www.freereg.org.uk where volunteer transcribers post their transcriptions of parish registers.

I did visit John's parents grave at St Nicholas Kelston and have attached a photo. The 2nd photo shows the position in the churchyard.
I have a lot more information on the BENCE family. Please send me an email directly if you would like more information.
Brian Bence