It seems that I have a fresh looking quadrant already with an adjustable pedal. However, the bolt was quite a way out so I adjusted it, and thus moved the biting point.

Now the clutch on the driveway does seem to bite higher than before but with a few side effects. The first is that the pedal sits quite high; I shall take it that the teeth mod has not been done to this. Finally there is a 'notch' where the biting point of the clutch is; From further reading I understand this is a trait of Helix clutches; maybe this is why the biting point was so low and thus why the clutch was not disengaging correctly.

Does the Helix clutch require care as to where the biting point is set, or does the above sound normal?

Now to hunt out an alloy quadrant...