Thanks Shona.
I had looked at Deorah Tomlinson and found most of what you have detailed here (apart from the birth in the Lying in Hospital) Rebecca's maiden name was Leveridge (or a variation of) and in 1761 a Mary Burbage married a William Leveridge at Yeovil (FreeReg) I know the name is slightly different but it does suggest to me that there may have a relationship between Rebecca and Deborah. There are a lot of Burbages and Leveridges in Yeovil mid 18th C, far more than there were Underhays!
Sadly the Baptisms on FreeReg @ Yeovil only seem to go back to 1780s so I can't find Deborah or Rebecca there. I thought I'd found Rebecca's parentage
http://www.genealogistsforum.co.uk/f...ecca+leveridge but I have since disproved this but cannot find another candidate. I still think that there is a Yeovil connection but can't prove it yet!
According FreeReg again, John Underhayes in your post above was born 1808 to a Mary Underhayes, no father named.
Where did you find the Ann Burbidge burial?