Listen to Nelly mate, exactly the same symptoms I had with mine .. except the only way I couls get it stopped was to put it in gear and stall it ...

Sounds like the exact same thing with the solenoid sticking ...

and Mark, whoever told you they are supposed to do it ... well I'm afraid he doesn't know his rear end from his elbow ... sorry ...

Oh, and according to my invoice from Nelly, they are just over £30 plus VAT ...

So not too terminal or expensive in the greater scheme of things ...

Good luck mate ...