Find Ancestors

Trying to find my dad who I have not seen since I was 3 years old (I can't even remember him!). His full name is/was RAYMOND PAUL WILLIAMS born on 7th (I think) July/August 1950, he married my mum, BETTY COTTAM in 1969 at Swinton Registrar Office. He had 3 children with Betty - MICHELLE WILLIAMS 2nd October 1969 (myself), THERESA WILLIAMS 15th December 1970 and DARREN WILLIAMS 11th November 1971. His dad was VIVIAN WILLIAMS who died around 1945 with cancer. Ray's mum was JOAN WILLIAMS (don't know maiden name). Ray had 2 half brothers (JULIAN WILLIAMS) and (TIMOTHY WILLIAMS), as well as a half sister (DONNA WILLIAMS, may be married now and have different surname). Donna at one point lived near Brixton prison. Ray had a step mother (GRACE WILLIAMS) and a step sister (?KATRINA). He lived in Hackney, London for a while at one point, and is originally from Hemel Hempstead, Hertfordshire, London. He was also known to have been living in Sheffield for a while. He was apparently a fanatical West Ham supporter and liked bird watching. I would really appreciate any help in contacting him; or Ray if you see this ad yourself and do not wish to be contacted please let me know and I can put this matter to a close. Thanks. Michelle.