How to Remove Mid Position Valve head

[daffs]

Hi,

I think my mid position valve is stuck, unfortunately it's a bit awkward to see but with a mirror & torch
I pretty sure the levers not moving as I switch between HW/CH.
It appears to be stuck in HW position.

It's a Drayton MA1 (screwfix).
I can get the top off, but how do I get it off the valve body?

Annoyingly this has just been replaced in attempting to fix my intermittent boiler cut out problem.
I'm not quite convinced yet but thought I'd ask now so i can get on with it tomorrow.
Thanks

 

[seco services]

on the oppersite side of the w m h is a black button push it in the actuator will come off.

 

[seco services]

whats the marker pointing to w m h ?

 

[daffs]

thanks!