Sorry no, never been cleaned before, except for full system flushes.
Is it the compression connections that make you think that, if so not the case.
Up to those connections came with the built up cylinder c/w pump, this air separator, zone valves and appropriate pipe between.
22mm copper pipe going up and past header tank and looping down so hot water falls into tank then from bottom of tank 15mm copper pipe to about 2" away from where the other left the system.
Is the corrosion/sludge caused then by the hot water passing through the air?
As Subject, have read other posts.
Running pump at slowest, faster gives more flow out of expansion pipe.
Boiler goes on and off so I assume its thermostat working.
Bleed radiators and pump.
Lowered level water in header tank when cold so when water comes from expansion pipe no water overflows...