Hi Linda, I'm back from my tea!
Great help from Lynda, who is a fantastic researcher.... Far better than me, but a couple of words of caution,
I've been where you are... So excited at leads and possible ancestors! Its so important to take a step back and work back from what you know for sure. (Before you spend too much money on records)
Your dads name was George Curran. You have him as born 1920's, before 1921 - no location on his profile at the minute. His parents you have as Edward Henry and Emma Eliza. Where did you gain the knowledge his first name may be Edward and middle name Henry? Given the record Lynda has found could he have been a George?
There is also a death record on familysearch for a George E Curran that ties in with the 1900's birth and 1930's death, and is registered in Holborn, same as the marriage to Emma E Leach. But note his middle name is E not H. (You have his death as Islington - not too far, but again is there a source for this?)
You've written on his profile that he may have been adopted, this 1911 census entry on ancestry is also in Holborn for George:
Damn!!! I still can't copy and paste on this old tablet
But go to familysearch, restrict search only to England, George Curran birth 1899-1901, go to 1911 census and bingo, we have a record of an adopted son of Edward and Adeline, so his adopted father was Edward, he was George! And why there is no birth record for George Curran in Holburn.... Onto searching for George 'Bubbers' born circa 1900?