A mystery has now arisen.
I tried rotating the crank to find TDC (with a long slim length of wood through No.1 spark plug hole) and, although the crank turns fine in an anti-clockwise direction, it will only turn a few degrees clockwise before coming to a dead stop and refusing to budge further.
I've rotated it 5 or 6 revolutions anticlockwise and it turns fine.
There are no locking pins in place and it turned just fine before I removed the crank pulley bolt.
If the timing has slipped, I should able to set it right when I adjust the camshafts, shouldn't I?
But why will it turn anti-clockwise ad infinitum, but locks up after a short rotation clockwise?
The answer appears to be that, with the crank pulley bolt removed, the timing belt is now able to slip on the crank pulley and was doing so when I turned the crank clockwise but, for some reason, didn't do so when I turned it anti-clockwise.
I tested it last night by turning the crank 90 degrees - and the cams didn't move even though the belt is still firmly in place on their pulleys.
Talking about the crank pulley, even with the bolt removed I can't get it off so I've sent off for a pulley puller.
When it arrives, I'll post further updates,