First, thank you, Ciderdrinker, for all your work on following this up. I really appreciate it.
Here's what I know. James Bailey showed up in the Taunton land tax records in 1800. I note that James and Isabella were married in September but I recall that the land tax records were mid-year (though I cannot find where I noted that). So that is a slight miss-fit.
Also, James had a son, William, who was born 1864-5. The 1851 census records say he was born at Taunton but I have found no record of his baptism there. That's another miss-fit.
Isabel Bailey died at Taunton in 1813, aged 49. That means she was born about 1764 and would have been about 20 if she was William's mother.
I suspect that, if the Melcombe Regis marriage is the correct one, then Isabel(la) is James' second wife. It could also be that James was Isabella's second husband. After all, The witnesses are two Grant girls (maybe Isabella's sisters).
The next steps, I suggest, are:
* to look for Isabel(la) Lambert or Grant baptised about 1764
* to look for a James Bailey, perfumer or hairdresser, in Weymouth
* to look for James Bailey in Weymouth land tax records pre-1800 (did you find anything?)
* to look for a marriage of Isabella Grant (?) to a Mr Lambert and his subsequent death
What do you think?
Regards
Doug