Hotpoint Aqualtis AQXXD 169 PM Machine Blocked Error?

Hotpoint Aqualtis AQXXD 169 PM Washing machine.

Coming up with "machine blocked error F7". This always happens when filling with water but the water does fill up in the dum.....almost certain pressure switch not seeing drum level. I can simulate this by turning off water main - same error. Pressure switch tested by bowing down it and it does switch..... when I blow down the tube down into the drum, I get a lot of resistance....is this normal?

I have fulshed out this tube with main water etc... and can get the machine to fill up throughit albeit slowly.

Pressure switch is definately not switching as I have my meter across it and thats when he eror comes up..... I can even blip the switch by shorting the contcats and the cyle then steps on.

What is inside the pressure tube point - how do I get in????

Pulling my hair out!!!

PS: fitted a new pressure switch (£12) just to be sure..... same problem.