The gears (in the hub) were slipping so while pedalling it would suddenly do a few extra revolutions without driving.
It was often difficult to get the hub gears to re-engage and drive.

Found chips of spring and lots of other debris in hub.
Cleaned all bits.
Had extra conical spring not in maintenance diagram. It goes on the outside of the cir clip on the brake side.
Some of the ratchet teeth were chipped:


Also you can see here how the emergency spring wire pawl retainer (put in near Agadir) could cause the pawls to stay out or drag. I cut some off this spring wire to reduce the possibility of it catching under a pawl.