The comments about not worrying about the hours was well received - talking to other students at denham most seem to tak between 20-30 hours to go solo and some a lot more
Part of the clue is in the above with you. It really does not matter how many hours you take.
As you said your circuits are good and precise its when you turn onto the final approach that the Gremlins hit.
Maybe have a chat with your instructor and do some circuits where you do not land.
ie all the approach and flying down the runway at 5 -10 feet.
It may help to try a big runway with clear approaches as Denham can be quite daunting?
Above all see it as fun not how many hours you are or are not taking
Pace