Help required for replacing union valves.

[Mitch1612]

Hello,
New here.
I have some older type single radiators in my home, that I want to keep.
The are supplied by 15mm copper pipe, into the valve, that has a 3/4 union type fitting.
I want to replace these fittings with TRV's and am having difficulties finding a direct replacement.
My floors are concrete, so I don't want to replace the rads with 15mm compression valves, as I believe I would need to alter the pipework.
Any of you guys have ideas?

Thanks in advance.
PS, I'm not a plumber!!!!!!!!!!!!!

 

[ShaunCorbs]

You won’t get any 3/4 union trvs so will need to adjust the pipework

 

[Ric2013]

Could you (stupid but it may work) put a straight TRV onto the pipework feeding the radiator without removing the existing valve? Might be a possible workaround if you can get the TRV into a position that is useable and don't mind it looking slightly unconventional (what WILL the neighbours think?!).