aseanaero - not a particular problem with the Wessex, unlike the starter relay that used to stick - the answer was stamping your feet on the cockpit floor which worked most of the time. Some crewmen used to take a fireaxe to the relay (percussive engineering), unfortunately not all of them knew which relay was the correct one and battered the main drive actuator instead!!
We still use the Gnome in the Sea King so there should be plenty around, there are a few modifications required because of the way they are mounted in the Wessex.