Jim Alexander wrote:

No this is d-i-y and we'd never be so stupid. Schedule your services before
the heating season begins.

To be honest I was trying to avoid having it serviced as I was planning
to replace the boiler in the spring and did not want to pay for a
service and possibly a power flush, particularly as this would have to
be done again when the boiler was changed.

I have already checked the pump is free by removing the inspection
screw and turning the spindle. I can also hear the pump turning. What I
can't check is whether the pump is stopped when it should be running.
I can think of two possible reasons for this; a faulty over-run
thermostat or a semi-knackered pump.

I would change the pump stat, as it is cheap, if it wasn't for the
horror stories I have read about problems when you start opening up the
Apollo Fanfare (CO leaks etc)and, according to the installation/service
guide on PartsArena, you have to remove the inner cover to get at any
of the thermostats. Does any one know a way round this?