Ok,

So I checked all the earth connections, etc etc, and today I did a test.
I disconnected the Amal/lektron whatever valve and tested it for both pressure and vacuum and it does not hold either one of them.

Then I connected the turbo pipe directly to the actuator and went for a spin.
The car does something like 0,5 or 0,7 boost but smooth and with no cutouts.
So I have a broken valve it seems.

The thing is, I can't find one for the small turbo cosworth and not even for the fiesta rs turbo. (I read somewhere that they are the same).

So what can I do?

Use a bleed valve? And disconnect the Amal valve?

Use a two or three port solenoid?

I'm biased here!