I've dealt with the MIB before and they are a nice bunch of people but it's worth noting the following:
PLEASE NOTE THE MIB WILL ONLY DEAL WITH REPAIR COSTS IF THE OTHER VEHICLE IS IDENTIFIED OR TRACED - ANY CLAIM IS SUBJECT TO A £300 Excess.
If you can't find the car that hit yours you don't have much of a chance.
Also if they cannot find the other vehicle it goes down as a "fault" claim.
By the way, do you know that you are "supposed" to disclose this sort of thing to your insurance companies anyway (the small print says have you or your vehicle been involved in any accident) this does not mean have you claimed.
Ok so I guess no-one does, but its another way the Ins company try to screw everyone anyway, if you say yes, they raise your premium, if you say no, and they find out you lied, then you aint insured.
I feel for you mate, hope you get it sorted out soon and it doesnt skint you.