Well i've got the car back!
Had a 2nd hand gear box, clutch, and flywheel fitted from a 2003 dti with 68000 on the clock (clutch looked nearly new).
Car runs and sounds better than it ever has done.
Turns out my gearbox had sprung a leak (although i never saw any oil patches) and had NO oil in it. This in turn made the gearbox start to seize, thus destorying my clutch and flywheel.
The clutch was as smooth as sheet metal and wafer thin, and the flywheel had about 1.5 inches of movement in it. Mechanic wondered how the hell the car was still working!
Anyhow, I've seen the parts and seen how bad they were to make sure I wasnt being ripped off.
£440 all in including gearbox oil and new driveshaft seals.