Hi Steve, only just got your reply (we're an hour ahead here so sleep was beckoning) and agree that the timing is normally at tdc. It's just, as I said, I've had a bit of spurious info saying that the crankshaft pully should be in the 3 o'clock position which is actually bdc! There is a datum mark at 9 o'clock which of course is tdc. However, with all the head bolts loose and the crank and injector pullies set, when I turned the cam shaft pully the exhaust valve lifted the head. I've got to go and carry on now so I think I'll let it lift the head and carry on until it lowers again and see if the notch is anywhere near the datum point. You never know, a fresh start could make all the difference! I'll let you know later how I got on and thanks for your help.