It was pointed out by the garage that the cambelt had some slack in it, and I was advised not to drive the car.

I was expecting the belt change at the next service (giving me another year to save!), but having checked the service history dates, it was 5 years since it was last done. Don't feel quite as robbed now, although the wallet has taken a hammering.
For anyone who's interested: £820 all in, including rollers, tensioners, dampers, waterpump, belts, bolts, coolant, labour, VAT. That's at GCS Engineering nr Horsham.
Major service was done at Audi Five Oaks, £440 all in. Their quote for the cambelt change wasn't too much more, but I know and trust GCS, and in these tough time, I like to support the smaller players too.
Oh, and I've got a small coolant leak from the oil cooler. Could be a gasket, could be a new cooler. Fingers crossed!