Cooking on gas!!!! Literally! Pressure adjustment key goes into the hole just to the left of the grey bolt looking thing. Water pisses out if the key is not inserted. Turn the grey knob until pressure rises to 2.5 bar, turn off grey tap, remove key, then using the red twist knob to release pressure to 1-1.5 bar. Turned it all off and bled rads again, turned it on but kept getting error indications that indicated control board.

reset about 5 times and it's now settled and rads are toasty, and hot water is scolding, yay! Thanks very much Toby and Alex. Whoever said u were a crap plumber needs teabagging!

thanks again guys, u probs saved me a fortune for a cowboy to change every module and component in there to see me off! Leg ends! Cheers!