Hi Andy glad you managed to get your insurance sorted. I just wanted to say that on a car like a C63 AMG I would personally get a tracker fitted.
Only my opinion but I wouldn't bother with tracker. Who ever has the succesfull means to steal it, it would probably not come back in a very nice condition.
If it worries you to that degree I would go the route of GAP insurance.
Can't wait to hear how it is when you get it... I too am insured with Admiral (Elephant Group) and on a commercial side I went with A-Plan also suggested previously....
Mark.