Hot Water but no heating

Apologies for starting a new topic that looks remarkably similar to others. Recently moved into a new house that has a boilermate 2 in it. The hot water works fine and is always hot. The heating however is a different matter. We have had the room thermostat up at 30 C but the heating still won't start. I believe that the issue is the CH pump, as of the two pumps on the front of the boiler, if I turn the lower one down, I can hear the motor change, however if I alter the top one (which I *think* is the CH one?) I hear no change in the motor.

Does this sound like it is the issue and if so, do you know what the rough cost of replacing this is?

Much appreciated,
Stan

Sounds like the heating pump.
Check if the is a supply?
Check to see if the pump is seized?
Try freeing it off.
New pump, depends on where you live etc.
Pump valve will probely leak so a drain down, new pump valves and pump may be the order of the day.
Upon draining down you may have sludge problems.
Another can of worms!
You may need cleaner put in.
Then flushing out later.
Then re filled and inhibitor put in.
All good stuff!
Mike