So an update...
... it did turn out to be a damaged coil... my stator must be a very older model as all the coils are soldered to the stator plates, i.e. no ring terminals are present.
something fell in and got lodged between the stator and the rotating magnet... tore one of the wires on one of the coils...
... not sure what happened here... I am always very careful not to drop and loose things into the engine compartment...
Thanks for all your help.