FWIW modern double panel rads are usually massively over-specced so unless you are using 80s rads or silly designer stuff you might get away without ripping them all out.
Just noticed this replacing 3 from build 70's single panel rads in our lounge for 2 double panel rads. Room now heats like a bastard. Will probably do the rest of the house 9ver the next 18-24months and then consider ASHP when the boiler goes.
FWIW modern double panel rads are usually massively over-specced so unless you are using 80s rads or silly designer stuff you might get away without ripping them all out.