Advice needed: Brakes/Garage

[AaronGS]

I would appreciate you guys advice/thoughts on the following.

The story so far:
Car went into garage 3rd Nov for investigation of suspected braking fault. Phoned 2 days later to say a piston is seized and they need rebuilding (Tarox 6pots) and they advice both calipers going back to the factory for this. The time quoted is 5-7days. I have a courtesy car so no issues there.
Now the garage is being told 'mid december' for the return of my brakes. The garage have put a set of standard brakes on so I can have my car back; I initially said fine but my insurance is invalid without the bigger brakes and its a pain getting back to garage to drop car off again. I am still to phone back and say its a no go (they can have their car back if thats the issue) but was wondering what other people would do in a similar situation as its ridiculous the increasing time for the job...

Cheers.

[Wazzzer]

how is your insurance invalid with the smaller brakes 

at the most it would be a mid term adjustment?

[AaronGS]

Aye, mid-term adjustment = ££ and I am short of cash. I guess I just don't see why I should be paying that when the lead times are extending without explanation.

Edit: just realised I didn't mention, the car runs ~350bhp and hence standard brakes are not popular with the insurance company...