Well I could not logically connect why the ac kicking in and causing an engine rev to be solved by cleaning the throttle. But I thought if it worked for Drone then worth a try. I only undid one jubilee clip and removed the hose from the throttle body. Few squirts of cleaning spray and a bit of gentle rubbing on what I could reach of the inside and the outer flap. Not sure what you lubed with silicon but I did not. Stuck back on and went for burn. Initially my aircon seemed to have stopped altogether - engine on and off - all good again with aircon...and no engine surges at low revs.
Its only done 28K and is an X reg 2000plate, but there was enough soot to leave a rag pretty dirty and in addition Im sure its responding quicker on acceleration.
So a big thanks to Drone and a problem solved - although Im still a bit bothered about the logic of it
