Antony wrote:
I think you may have a possible solution. All the rads (except one)
have TRVs on them although I suspect this was something the previous
owner added and not a Redrow standard fitment. This probably means
that there isn't any special plumbing to handle such a situation. The
only radiator not to have a TRV is the small one in the hallway where
the thermostat is. Since I keep the lounge door closed, the
thermostat is actually in the coldest part of the house.

Is the following a realistic scenario ?

Themostat in hallway demands heat. TRVs say it's too hot and close
down although the hallway is still cooler so the boiler stays on.
Since there is now only one small radiator to take the heat away, the
boiler overheats because the heat cannot be taken away fast enough.
When this happens, the pump keeps running even though the boiler is
not lit.

Is the solution therefore to set the TRVs to maximum and turn the
hallway thermostat down a touch to prevent the rooms getting too warm.

Thanks

Antony

Wouldn't it make more sense to have the thermostat in the lounge where it
can regulate the temp where someone cares what it is?
Many years ago I had a house where thermostat was in the hall but I couldn't
see the logic in that.
In all my houses subsequently its been in the lounge.