Starter-Slight Buzzing but not engaging or turning

Mk1 Clipper Cab, Manual Box. Not making any sound at all when trying to start.

On the car:
-Cleaned all connectioned, Nuts, washers etc.
Then Multimeter out, I've checked:
-Earth to body of Starter and Earth Terminal, fine.
-Live to Main Terminal, fine
-Ignition live (the spade connection), fine

Off car, rigged with jump leads on a bench:
-Shorted ignition to live, it buzzes quietly but doesn't throw out or spin up?

Am I missing something?

I've given it a few wallops for good measure, as suggested in other posts.

While I was taking it off the section where the terminals are rotated slightly, have turned it back to where I think it was before…

It does seem to have an extra spade connector (Seperate from the Ignition connection), but I don't have anything to connect to that…(?)

Oh and I can't get the solenoid off as the screws are knackered  

Scrub that, assumed the worse and took the starter apart, one of the brushes was loose in the casing, all back together and now it turns over like a beaut.  Won't start though..back to square 1…