Blimey - 950 miles already!
We got our EX a couple of weeks afore you and we've done 5,240 miles!
Can't say that we've noticed anything with the rear brakes though. Everything is just hunkey-dory!
The previous Jazz, an ES, did 27,000 miles and hadn't any problems with the rear brakes either. But, the handbrake seems much more 'solid' in this one.