TR3 - starter motor trouble

[anders@ull.biomeklab.aau.dk (Anders Odgaard)]

The starter motor on my 1956 TR3 has failed. When pushing the starter button,
the motor runs willingly, but it doesn't turn the engine.

What is the likely cause of this? Is reconditioning a starter motor for the
average DIY person? If not, does anyone know a good source for reconditioned
/NOS starter motors in Europe? What should I expect to pay?

Thanks,

Anders, Aarhus, Denmark

1956 TR3
1983 Rover 3500 SE