Here’s an extract found by Mary (possibly a distant relative!) in Exeter library.
This shows that William Hancock had a son (as I’d hoped) and that son had two sons, Edward and John who were children when their father died in 1660. I’ve been in contact with the Local Studies Centre in Barnstaple who have said that they have parish records from Comber Martin dating back to 1670, so there’s a fair chance that I should be able to find some records of whether Edward and John married and had children. Definitely a trip to Devon coming up soon!