Thanks Amondg. I am also interested in tracing the Bunkers back as well. However, I had got no further back than Elizabeth Richardson's parents John and Ann Bunker because there were several John Bunkers, and John and Ann Bunkers in that part of Devon then.
The marriage you found of John Bunker and Ann Lethbridge on 1 October 1802 in Holcombe, Devon, certainly places them as the parents of Mary Ann Bunker (1802-1848).
However, according to the 1851 census Elizabeth Bunker, the wife of William Richardson (1797-1869) was born in Wembury, Devon c 1799. She died age 54 in June 1853, Plympton St Mary Union. Elizabeth, dau of John and Ann Bunker, was baptised on June 11 1798 in Wembury, Devon.
I am not sure what to make of this. It could be that Elizabeth Bunker (1798-1853) and Mary Ann Bunker (1802-1848) were related but not sisters.
John Bunker married Ann Cleave on 14 June 1790 at St. Werburgh's Church, Wembury, Devon. They had eight children baptised in Wembury:
Mary Bunker 1791-1792
John Bunker 1793-1844
Mary Bunker 1796-1797
Elizabeth Bunker 1798-1853, married William Richardson on 15 July 1819, East Stonehouse Devon
Sally Hickson Bunker 1802-
Mary Bunker 1805-1881
William Bunker 1807-1811
William Bunker 1811-1883
I would welcome any thoughts and suggestions.