My name is Linda Barber and I think the Walter Damms you are talking about is my great grandmothers brother.
I have his death certificate and I find it so sad. It says he was found exposed on the 12th March 1864 in Nether Hallam and came to his death by drowning. he was 21 years old. He apparently was buried in Stannington Churchyard.
I have not seen his birth cetificate but there has always been a story about GG Elizabeth having a brother who was drowned in in the Dam Flask tragedy.
This is definitly the Walter in your message I didn't know he married and that there was any children. I would love to know more.
Looking forward to hearing from you