Now you have the starter off Mav you can try and see where the problem lies either solenoid or motor.
Its best to place the starter in a vice, as they do tend to jump around a bit on the floor. With a pair of Jump leads and a good battery, attach the negative lead to the starter motor body such as the flange where it bolts on to the engine, and connect the other end of the jump lead to the negative battery terminal. The positive lead should then be placed on to the large connection where the battery cable attaches to the solenoid and the other end on to the positive battery terminal. With a piece of wire or the like short from the positive connection on the starter to the small solenoid connection on the starter this should throw the pinion out and turn the starter.
If there is no joy with the solenoid working the starter, then you can short across the two large connections the one your jump lead is on and the other large connection next to it, this should be done with a spanner or screwdriver or the like as a piece of wire will melt and burn your hands, you should have a few sparks and then the motor should spin up. If there is no joy and the motor does not turn then there is a problem with the motor if it does spin up then it is just the solenoid at fault. No sparks and no motor spinning suggest a problem with the brushes, lots of sparks and no motor spinning suggest a short in the windings of the motor.
