separate zones in heating system

[^woody^]

Hmm yes thinking about it more that radiator sounds like it is already effectively zoned off rather thank being on a circuit with other radiators. In which case a smart TRV would work.

Tado is pretty good value, a base control thermostat in the main house and 1 smart TRV for the garden room would be about £200 and very simple to install.

The Wiser system is cheaper for the start up system of the control box, room stat and two TRV's at £200. Plus additional TRV's are only £40 which are the cheapest available.

The Tado system needs the room stat to be wired in permanently, but the Wiser room stat does not - which is why I went for Wiser. But Tado is a bit more polished and established. Otherwise the two perform the same.
We may be a bit OT now though

 

[ivixor]

Actually the Tado room stat can be wireless with the Tado Extension kit. The extension kit plugs in place of a programmer, and the thermostat can be anywhere.

Can't believe that OP has no thermostat for the house. Very strange setup with the zone valve too.

 

[^woody^]

Actually the Tado room stat can be wireless with the Tado Extension kit. The extension kit plugs in place of a programmer, and the thermostat can be anywhere.

It may be wireless for the connection, but does it need hardwiring for power?

 

[ivixor]

Nope, it's powered by 3 AAA's.