All of you who called an earth fault were right, based on the test suggested by Graham. Thanks.
That's not to say that the solenoid isn't about to give up, or that I shouldn't upgrade the starter but for now I think a new set of earth cables is a good investment.
The current set up is a single Earth cable from the battery to a nut on the bulkhead from which one cable goes to the bell housing and another to the bottom of the bulkhead on the offside. Is there a better way of doing it?
Mark
Good, that's the easy bit. When you replace the lead from the battery, get a heavy duty one and take it to the bell housing. You can then run a lighter lead (such as size already fitted) back to the bulkhead (earth return for lights, clocks etc.) Clean all the connections, apply Vaseline or battery terminal grease to the battery terminals after you fit the new connector.
From your configuration I'm assuming a 4 seater?
On my old 2 seater, the battery was by the rear axle with the battery earth connected to the chassis where one of the old type dampers was mounted. An earth then ran from the gearbox to the chassis in the engine bay. Many found that long run (and the rather weedy battery earth lead) led to exactly the problems you have had and a good number of cars have an additional earth lead run the length of the car to connect the battery earth direct to the vicinity of the bellhousing/engine block.
