Thanks everyone so far for their assistance.
Unfortunately I am not at home but after a quick search online it looks as if the thermostat is a Siemens RAA20 Room Thermostat which does not require a neutral in its installation.
Looking briefly at the wiring diagram of the boiler I can only...
Apologies if something like this has been posted before but I have done a search and cant seem to answer my problems....
Our current boiler is a Ravenheat LS80 Combi boiler (Don't worry I am aware of what they are like....)
This is currently controlled by a siemens room thermostat with 3...