Distributor rotor not spinning...why?

[junar]

UK RAC said car was not getting spark. He said crank sensor or ignition (amplifier) module fault.

Tested crank sensor, got reading. Got replacement module still no start Tested each plug for any sign of life, yes, there's spark but not from 2 & 4. Reason was the rotor not spinning and stuck in between 1 & 3.

Are these the possible causes:
Auxilliary shaft (I hope not, big job!) or Distributor shaft? or anywhere else?

Please help...