Am I right in thinking that the wireless receiver/extension that I can wire into the boiler would only be of use if I have a wireless thermostat or for hot water?

T4360/T6360 - Flexel

The wired receiver can be connected at any convenient point, usually next to the boiler, and then the thermostat can be positioned in the best location without the need to run a new cable out to it. Of course, a step further up is to go 'Nest'-type which also gives you phone App control, but that's prob a step too far?

Although not good practice, you could use the earth wire as the switched live but you should put red sleeving or insulating tape round both ends to show it is not an earth wire. This would leave me with an internet bridge plugged into my router, a wired thermostat and 8 Smart radiator thermostats. I would like to lower the temperature that the thermostat is set to turn on the heating, but having removed the front cover, it isn't obvious how to do this.

Honeywell Home 1-Channel Wired Mechanical Room Thermostat Honeywell Home 1-Channel Wired Mechanical Room Thermostat

It also has a variable temperature control range from 10 to 30 degrees Celsius, and a switchable voltage operation between 220 and 240 volts, making it compatible with most types of central heating systems. lots and lots of options, from the Honeywell DT90e, but I'd suggest you consider a programmable stat since you are going this far.The T6360 is a mains voltage room thermostat designed to give automatic temperature control of domestic wet central heating systems. Even when the room temp is well below 20, the heating still doesn't come on, so I think it will be a replacement! At the moment I guess your timer is mounted on the boiler, so that does things like switch ON at 7am and OFF at 9am and ON at 5pm and OFF at 11pm, for example? The thermostat comes with a range of customizable settings, allowing users to program heating and cooling schedules to suit their needs.

Honeywell T6360 (English - 4 pages) User manual Honeywell T6360 (English - 4 pages)

And is your house warm when you come back - or do you have to turn the room stat back UP as soon as you are in? I suspect the thermostat isn't correctly calibrated at the moment as I seem to need to turn it right up to the top for the heating to come on. Place the thermostat about one and a half metres above the floor, not in the sun and not on an outside wall. How do I know what the current temperature setting is to enable me to put the new dial on the underlaying knob?However from your description it sounds as if you may have the version with the separate wired control box like this. My new thermostat, when switched to the lowest settind (off) still heats the radiators (normally overnight. And the existing boiler time control is set to be permanently 'on' 24/7 allowing the Wiser to take full control. The thermostat only switches on when, for example, the difference deviates more than 2˚C from the set room temperature. Currently, the earth wire (yellow/green) goes to the earth connection, neutral (blue) goes to connection 3 and the live (brown) wire goes to connection 1.