As to the problem of the heater heating other items, I have tested a TRV with a standard head, and set to around 2.5 it starts to close at around 18.5ºC and does not fully close until around 21.5ºC so would not really help to stop flow to other radiators, the electronic heads are better, the eQ-3 and Terrier i30 were cheap stand-alone units, but the price after Brexit went up. And the eQ-3 Bluetooth version will only connect to one phone, so although only £15 in 2019, getting a Wi-Fi version may be better. The Kasa one I have, eats batteries, and the Energenie, Kasa, and Wiser TRV heads all needed their own hub to work, the Energenie will work with PC, as well as phone, the other two are phone or tablet only, there are emulators but the emulator is so slow to load, in real terms they will not work with a PC. But the Energenie had no option to manually set, the others do.