Broken cambelt on Rover 218 TD

[Medric]

Hi
A friend of mine has suffered a broken timing belt on his Rover 218 Turbo Diesel (K reg). It was towed to a garage and the mechanic reckons it will cost £1200 to fix. I seems very steep to me.
Has anyone experienced this breakdown and if so what damage was caused. Car is only worth about £500. We're thinking of just replacing belt and trying it to see if it runs. What does anyone think of this idea.

Thanks
Dave