If I ever find a plumber... the plan is to use surface mountings for the boiler flow and return pipes. Pipe insulation sleeves look to be 19mm thick. Plastic pipe clips appear too short for this to work. Stand offs need a lot of fiddly fitting.
Anyone come across a tall plastic stand off clip in 22mm?
Also, what is a sensible spacing? Insulation comes in 1m lengths which seems overlong for an otherwise unsupported pipe.