Ok quick update, managed to remove the advance valve with the pump in situ, quite suprised to find another mini filter in there as well. This was caked in a brown substance which came of almost in a little sheet. My hope were raised by this and after a good clean i reassembled.
The car started, all readings were spot on for about three minutes then bang, back to previous readings :doh.
Now then, I think whatever the gunge was is residing actually in the pump/fuel lines, I am getting a replacment pump on thursday so i can either use it`s advance valve or if needed the whole pump.