Tricky Dicky wrote in
:

You used to be able to get a radiator valve that had valve and
lockshield combined that had a tube that extended into the radiator.
We had one on a radiator in the last house but I have not seen one for
years now, certainly not from the usual suspects, a good plumbers
merchant might have some stock. Whether it will actually save you some
space, I don't know? If the plan was to have a TRV then you will not
get one with this sort of valve. Other options to explore are radiator
adaptors plenty of extending ones about if you can get an angled one
you should be able to tuck the valves below the radiator as an angled
adaptor would probably occupy less space than a valve.

Richard


Our house was plumbed with these - now replaces as there is not a
thermostatic version of them and the regulations reguire installers to
fit thermostatic valves despite people misusing them. I think they were
called Twinfast Valves. I had no problems - but I think many people
misunderstood them and / or the internal tube got broken - or even
never installed.
We are persuing some 90degree chrome elbows.