You have re-awakened my interest in the Dollings and I have been having a fresh look at them.
I presume your 3xgreat grandfather, William, is shown as "fatherless" on his marriage certificate, leading you to deduce he was the son of Elizabeth. Interestingly William and Martha also had a son William baptised in 1824 and yet, after a rather admittedly superficial search. I can only find one matching entry in both 1841 and 1851, when logic dictates there should be two. Strange.
Family Search has a record of a marriage, by licence, between Edward Binmore and Jane Dolling, age 21, of Kingsteignton, in Exeter in 1833. The name is recorded/transcribed as Benmore on the censuses. Her year of birth is consistently 1812 and although her place of birth is given as Kingsteignton in 1851, it appears as Trusham in 1861. I think this is "Jenny" born Trusham 1812.
PS. I have just found a William DOLING, age 15, shoemakers apprentice, living in household headed by Robert Cleave, farmer, "Tucketts", Exminster. (Trusham civil parish) in 1841. Source - FreeCen. Could that be your 3xgreat grandfather?
PPS. I've just re-read you original post and noticed the mention of Jame Vines.