Sorry but I agree with them.
Your car is driveable so when the parts are in they will fit them for you and your car will be back to full spec.
Courtesy cars are a finite resource, how would you like it if your car wasn't driveable but all the courtesy cars were out with people who didn't...
Racing Brake already do :)
I have them on my car, don't think they will fit on an NA1 but it would be a good excuse for an upgrade to the later sized discs for you :)
Depending on your Insurer they won't replace all those items.
Exhaust might even be OEM replacement, even then you might have to make a contribution.
Wheels and tyres, how come ??
Tyres will only ever be replaced at a percentage, Insurance will never pay for 4 new wheels and tyres (well unless...
I bought mine direct from team dynamics at Brands Hatch a couple of years ago.
Have you asked them directly, they will no doubt be there this weekend again.