Thanks for the replies,
At the moment im (besides work which is what im supposed to be doing now) looking into all those engines and reading up on collision detection etc as nearly every engine in a game has this!
My plan is to have the design side of things finished by the end of summer and start programming/ testing then going back and adding a few more things etc. Accuracy is something i am aiming for as well as everything to be as real-time as possible.
Anyway thanks for the info