Washer pump earth

Quick one: can anyone tell me the location of the earthing point for the washer pump on a Series III? It's spontaneously stopped working and I assume crusty earth to be the issue. However, it goes off into the loom so that I can't find it! Everything else is working so I'm assuming it's not a shared point...

IIRC it earths on the front Radiator panel along with the headlights. You could run a new wire in, using the washer bottle fixing as an earth.

I thought it was that one but my lights are working... Perhaps it is knackered!

Connect it directly to a 12v power source, battery or battery charger to test the pump.