How to trace an adopted person?

[Magsnags]

Hiya I just joined this site today and sorry to ask a question. My dad was born in January 1942. In 1947 his mum re-married and his new dad legally adopted him, a year later his sister (now deceased) was born.
His mum never really spoke much about his real dad, all he knows was that he was a Canadian airforce man and went missing in action just before he was born (he's pretty sure his dad never met him).  I wondered if his mum hadn't really been married to him (as there were lots of illegitimate babies born in the war) but my dad remembers she was given his RAF bible and a photo of his dad's house in Saskatchewan where there was a door in the roof so the family could get out in midwinter so they must have been married to get that!
My problem is all dad knows is that his surname was Davis and the family was originally from Wales before emigrating to Canada in the 20's. I found one Davis in the Canadian airforce from Saskatchewan but it mentioned his wife and family there so that couldn't have been him.
How easy is it to find adoption records (if you can)? I looked at marriage records to find them - dad thinks they married 1940/41 in Bermondsey as thats where his mum was from but I'm not sure where to start. And I have been told by my husband it's got to be free or I can't do it - he thinks it's all a waste of time!
Thankyou so much
Maggie   

[CaroleW]

Hi and welcome to Rootschat

If they were legally married - the second marriage cert in 1947 should show her as a widow.  If it doesn't - they were not married

It will also show her fathers name which will give you her maiden surname.  If it's the same surname that she used when she married - that is double proof there was no first marriage

If they married in England - you should be able to find the first marriage if there was one

When you have his name - if he died in WW2 - you may be able to find him on www.cwgc.org

What about your dad's birth certificate - there should be a copy of the original entry somewhere?