Hello, Benita - Newton Abbot is a town in south Devon (not Cornwall). I have traced Dalby relatives in that area - descendants of Augustus Dalby born 1779 in Howden, east Yorkshire. He served as a Master in the Royal Navy during the Napoleonic Wars, and retired to Cornwall. His two younger sons William and Nicholas lived in England (his eldest son Henry emigrated to New Zealand in 1841). William Bennett Dalby (born Saltash, Cornwall, 1824) was a Royal Navy surgeon and lived all his lie in Cornwall and devon, dying in Newton Abbot in 1884. He had ten children including 5 sons. I haven't been able to trace all their descendants, but I suspect that you will find a connection. If and when you do, please contact me off-board and I can send you a great deal of information about the Dalby family. Augustus was an elder brother of my ancestor Octavius Dalby - one of whose sons George Octavious emigrated to Adelaide in the 1850s.
I have checked Free BMD and Doric H W Dalby was born in Epping in 1931. This is in Essex, and is now an outer suburb of London: a long way from Newton Abbot! It may be that you are descendant of Nicholas Bennett Dalby, born 1826. He was a Major in the Royal Marines, and retired to Bishops Stortford, Hertfordshire (in the 1881 census), not very far from Epping. Apart from one daughter Nelly Lyttelton Bennett Dalby born in Hove, Sussex in 1862, I have no information about any other of Nicholas's children. However, I would suggest that if you find any Dalby ancestors with middle name 'Lyttelton' or 'Bennett' there's a good chance that they are the same family!
Best of luck - Stephen Henley