Mid Position Valve Not Switching - No CH?

Hi,
Need some help with the below.

I have hot water, but no central heating. Common problem you say, but i have some strange readings across my mid position valve.

The valve i have is the Drayton mid position valve, as mentioned above i have not CH but plenty of HW. The valve seems locked to the far left hand side, whether i turn the CH on or off the valve stays locked.
I have had the valve apart and everything is fine, no signs of damage and manually it actuates.

With everything looking ok, visually, i have tested, the results are below.

CH ON - Orange 240v White 240v Grey 66v & Blue 0v
CH OFF - Orange 240v White 26v Grey 12v & Blue 0v
HW ON - Orange 240v White 26v Grey 12v & Blue 0v
HW OFF - Orange 240v White 26v Grey 12v & Blue 0v

Strange readings?? I have tested this with 2 meters now and still getting the same results.
I have now taken the mid position off again and manually turned it to the far right, but upon putting the CH back on it drives straight back to the far left.

I dont wanna pay for someone to come in and resolve for me so your help in this matter would be greatly appreciated.

Many Thanks