The
instructions are here what you have is a shared frequency for the signals between base and thermostat, and some filters that can be set so the base only acts on signals intended for it to use. I have not used this thermostat, however I have had problems with wireless thermostats, the old Honeywell one had a fail safe built in, so if no signal received every ½ hour it auto closed down, and the signal was repeated, every so often, so if some thing did block the signal, it would send it a second time.
The cheaper programmable thermostat I bought however did not have the fail safe system built in, and the heating could both stick on or off if the receiver missed the command sent, turning heat up/down or down/up forcing a second signal to be sent would correct the fault, but clearly not a very good situation.
My cure was to have two wall thermostats in parallel, and use TRV's to stop rooms over heating, and when I moved house I made very sure the thermostat is hard wired, even if not in the best place.
With the Horstmann HRFS1 I had it was clearly faulty, gradually it had to be moved closer and closer to the receiver to work, however it was the lack of fail safe which was the real problem, we had it free standing to start with, and likely mother had knocked it off the table a few times, had it stopped working I would have simply replaced, but it never stopped, just the RF link got weaker and weaker.
With my Nest gen 3, although I have it hard wired, it can be used wireless, however pressing the centre of the heat link (bit hard wired to boiler) will switch on heating directly, so I can turn on heating even if thermostat fails. I think the idea of an over ride is good, today the TRV stops over heating so no good reason not to have manual over ride.