And the winner is
nigel.
The crank pulley was indeed the rattle. It wasn't disintegrating as described, but the bolt was tight but not firm to the washer
Here is my situation as it stands:
I've had the car for 6 months and 11000 miles.
The guy I have given this job to (pulley, timing belt, water pump, which is leaking) has managed to snap the crank bolt off using his air gun, and can't get the rest of the bolt out.
The service history is an odd one - owned and maintained by a fire service, they tell me they have the correct interval on their paperwork for a timing belt, 96k, and as such would not have changed it. This would, i'm led to believe mean that this pulley would likely have never been removed before, but the guy is claiming the bolt has broken because it was loctited in, which is something you just don't do with lower bolts apparantly.
I now don't know what to believe. He seems genuine, the council that have the records of the service history seem genuine too and the guy now wants to charge me 3-400 quid to remove the whole engine to send it to an engineer that only *might* be able to get the bolt out. Failing that, new DW engine.
How the hell did I end up in this mess???
Please feel free to point out anything obvious that I have missed through having no idea what i'm talking about - this is like a jigsaw to me.