you can claim up to 3 years after,
i hit a kid that ran out in from of me 6 years ago ( not my fault and she was ok)
she was 6, i had a fireman see it wasnt my fault so never even had to give a statment to the police ( here comes the bent bit) even though it wasn't my fault i was told by the assessor that came to look at my car and were it happened etc that even though she was 6 years old, in 12 years time when she turns 18 she has 3 years to claim for compensation. sounds fucked up and it is, but thats the way things are now
(know it has nothing to do with the post just though i would share it as i wasn't a nice thing to have happened to me and wouldn't wish it on anyone)