The starter motor on my series 2 is starting to play up a bit. Sometimes the motor spins but does not turn the engine. A quick switch into a gear and rock of the car is often enough to re-engage it, but very occasionally a tap with one of my trusty whackommeters is required to unstick it. I don't mind an occasional turn of the starting handle to get it going, but my daughter suspects it may not so cool if having to do this in the 6th form car park in front of KA and Corsa kids ever becomes neccessary

(But then she knows how to replace a head gasket and re-sit valves in the head, which most of them don't, poor things...) As it spins well, I don't think it needs a full recondition, but obviously needs some lubrication of a sort. What is the best way to do this?
Paul