I realise that since you posted your message a year ago, this may not be received, and you have probably long forgotten about Ambrose Dallyn's descendants, but there's no harm in posting. I don't know if I am related to Ambrose Dallyn, but I feel it is likely because my great-grandfather, Alfred Dallyn, was born in West Buckland, to the south of Challacombe, along the A361. He was born in 1882. Hope this is of some use! Please contact me at firstname.lastname@example.org if you think he could be related to Ambrose. The same request goes to anyone else with knowledge of Alfred Dallyn's ancestors. Thank you!