BMW E36 Starter grinding noise

'96 BMW E36 M43 318i
My starter started Making a grinding noise some time ago every time I try to start the car, so I take my hand off the ignition and try again. second time the starter will turn the engine and start the engine.

So I changed the starter Motor/ The battery / The Ignition switch / checked all the wires and cleaned all engine earth's but still I get the same symptoms.

Now the obvious problem would be that the Flywheel has been damaged, but I did rotate the engine with the starter off and I didn't see any damage to the teeth. I think its unlikely that the flywheel rests in the exact same place every time I turn the engine off .. I'm thinking this is a intermittent wiring problem that the power to the Solenoid is insufficient to push the solenoid in fully. Is this plausible ? how should I go about diagnosing the problem ?

Thanks