I am an adoptee too. Both of my birth parents passed away in the 1980s, but I used 192.com when tracing my paternal line and located an uncle from an address listed on an electoral register.
If I remember correctly, you get the full address from the electoral register and names of other registered voters at the same address.
It took a couple of letters to different people to get the right one, but I have subsequently met my uncle and his wife, had a lot of information about my birth father and seen photographs of him.
The cost of the credits was a small price to pay, to be honest.
Good luck with your research,