It came in response to a call for help I placed on a forum on the UK-based family history website http://www.rootschat.com/.
Another poster responded:
I noticed a burial in Jan 1810 for a Charlotte MAWBEY at Christ Church, Southwark, Surrey, perhaps it is worth following up, speculating that perhaps she was George's mother.
Noticed also a christening and a burial for a baby in Dec 1805, Joseph MAWBEY, a son for Joseph and Charlotte MAWBEY, again SURREY ...
Based on information in George Mawbey's death certificate, he was born in 1809 in Surrey.
Did his widowed father have to raise him?
Does this mean there were no siblings?
A lot more digging to do ...