I've not had the whole head off, just the cover.
I presume removing the head is as simple as a couple of screws?
I think the valve body is turning ok as the valve will open without any problems if it is closed and the HW comes on but I'll check it tonight.
Recently been having problems with the hot water not turning off when it should.
Noticed that when it comes on the actuator (the system has two 2-way valves - one for CH one for HW) on the hot water feed clicks loudly and does not return when the water should go off.
This seems to also...