Phil Addison wrote:

Plastic and copper pipe is inter-operable so should fit the same if you
have 10mm TRVs. They are more commonly available as 15mm though which
you could use with a 15/10mm reducer.

Thanks for that Phil.

One final bit of info, will I need to cut the plastic pipe to fit the
new olive and nut on for the compression fitting into the TRV/Radiator
Valve? I believe the pipe is HEP20.

If I do have to cut I may need extra pipe for the downstairs rads. They
have elbows at 90 degrees to allow the pipe to go into the walls. The
upstairs have extra length which I can pull through the floor, they go
directly down.

Looking around on the net, it appears 50m is the smallest length of
10mm pipe I can get, clearly I need less than a metre. Any idea where I
can find or aquire "cut offs"?

Also are the Sentinel X400 and X100 products ok for use with plastic
piped systems?

Cheers for the help.

Mike