How can I find out more info on WW2 soldier?

Basically, I want to find out a bit more information about my great-uncle who died in world war 2. I know his name, age, date of death, regiment, service number and rank (I found his record on the Commonwealth war graves commission) but would like a bit more info on him. Is there any more websites that would help? He was British but died in Hamburg by the way. Thanks in advance!