Martin wrote:
Correct me if I'm wrong, but I thought you must not fit a TRV to the
radiator in the room/area where your CH thermostat is located for obvious
reasons.

Martin

You're right, they apparently fight. I do actually use the kitchen rad
to heat the side hall/downstairs WC at the moment, and the stat is in
the WC (conviently close to the boiler in the room next to the WC). No
rad in the WC, the side hall is heated via the kitchen, and the kitchen
is the biggest room that's also north facing, so always the last to
come up to temp despite being the 2 or 3rd closest rad to the boiler
(greatest heat losses from that room so always starts from a colder
temperature).

Despite effectively being one area, by the time the TRV brings the room
up to temp, the lag in that heat reaching the side hall/WC and thus the
stat is just right in order to then shut the boiler off. Whilst the
kitchen is coming up to temp, the other rads have been cycling on and
off quite a bit (usually prematurely, due to the fierce heat from the
rads, which is still only a theory of mine). All in all it works
really well, but only because of the specific environmental conditions
that are present with the kitchen/hall/wc/stat.

It's not practical to have the stat in the room without the TRV on the
rad - that's the bathroom, so wild fluctuations in temp due to window
being open to ventilate to prevent condensation, as well as heat from
having a bath, for example.