THANKS IAN!! I think it is all wired up and connected correctly, do I need to set the boiler to any particular setting to get the heating to come on or off? at the moment it is set to the timer but ideally I would want that off entirely.
UPDATE: It is working, I have it set to on and the Nest...
SOLUTION:
The solution is the following:
Could not have come up with it without the help of @ianmcd
Hi all,
I have had my boiler switched out from an very old (1990s) boiler to a Glow Worm 30c.
I had a Nest configured on this by an official installer, I believe he used the Y Plan...