When I had the casing off of the actuator, the heat was coming
from the silver coloured drum shaped object - presumably the motor.

It sounds like the head is totally knackered. Persist with removing the
thing. Any springs are part of the head and it is of no relevence if they
are damaged or lost.

Once the head is off, make sure the spindle turns relatively easily. If so,
you can probably just put a new head on it. You might even get away with
replacing just the motor bit. It is called a "synchron motor" and is easy to
source if you don't mind a little soldering.

Christian.