"I have replaced a 2 port 22mm Horstmann motorised valve. The newer model benefits from being screw retained motor to the valve beneath, but the valve casting is too tight to easily fit the pipe, and why oh why have they changed the nut thread between the old and new models? I was hoping to stick with the same brand and simply unscrew the old unit then fit the new, but because the thread size was different I had to cut off the olives, remove the original nuts and replace with new. Very frustrating as I was working in a tight space and had to dis-assemble some of the pipework. A 10 minute job took an hour!"