Installed my Nest Thermostat today. Was a bit of confusion because I thought I should be connecting it straight to the boiler so I took the existing one off and wired the Nest in place, hit next on the app and it told me I shouldn't have done that and what I actually needed to do was set the existing panel to continuous and also install the Nest. So put the original Honeywell panel back on and and took off the temperature control box and put the Nest there instead, but the setup wasn't working. The temperature dial box I took off seems to be redundant and not taken off when this flat was converted I guess? I mean I've never tried using and following the trunken I can't see how it might reach the boiler controls, to put the heating on I would jus go to the Honeywell panel and slide the switch to continous until warm enough then turn it off.
So I scrapped the Nest instructions and once again took off the old Honeywell panel and put Nest there again and now it's working. The Nest app is working fine and it's working through Alexa so jobs a gooden.