If looked after what sort of mileage can usually be expected out of a belt ??

I'm pretty sure belt change is every 65,000 KM or there abouts. They retail in The States for around $150 I think.

All things being equal, a belt should last 100,000kms or more. They're generally pretty reliable but a bastard stone or something in the pulleys can wear an edge and snap a belt in no time.