Standard Thermostatic Radiator Valve Replacement Head Only (TRV 2 WAY)

Had some specialists come in quoting me 6k to replace my “broken” radiator. Bought one of these - turns out it was just an old valve issue, fixed my radiator and saved 6k.

Didn’t look like it would fit, but it was a more up to date version and fit fine.

I have a myson radiator and the previous TRV 2 Way head broke. This part looks almost exactly the same except that it seems the thread only goes on about a turn as some others have noticed. I tried turning the valve to off to pull in it's pin, pushing it down onto the valve body while gently reverse screwing the gnurled ring until it dropped past the start of the thread, before screwing in the right direction. It still binds up...even with a little machine oil. I suspect the thread pitch is slightly different on these. It seems to let the heat turn on, however, where the older one wouldn't, and it saves me from having to replace the valve body (although maybe a new one would have the same thread).