VW TDI Engine Advice

Been offered a 2.0 Tdi Passat at a not to be missed price. Its on 05 reg i think the engine code is BKD!! Need a family bus etc so could be just what i'm after!

Anyway, heres the downside, the engines siezed!! all I know is that it was recently serviced (cam belt etc) in Feb, it has 130k on the clock which is naff all for a VW derv. Its a company car so has been regularly serviced by VW etc and mainly motorway miles... Now all I know about the siezure is that the garage that has inspected it has assumed the oil pump has failed as the top of the engine was bone dry and there was plenty of oil in the sump.
So my questions are:

What runs the oil pump on these engines? cam / crank / timing belt??
If an oil pump failure has caused this failure what would be the likely damage? im guessing crank, bearings, turbo??
Is it better just to replace the engine after a failure like this?

Any other hints tips or tricks would be appreciated!

there is a balance shaft in the sump on them and the oil pump is driven of it the shaft that drives the pump rounds off it is comen on that engine the engine will be scrap or you could rebuild it