If you disconnect the WG line so that no boost can get to it, it will remain shut - as you said.
When you go WOT, it should boost uncontrollably - upwards of 30 psi if you're not careful. You either have a boost leak, or an exhaust leak.
Either way, the hardware isn't working if you get no/little boost with the WG line disconnected.
Yes. I was pretty sure It wasn't a software problem, as it requests huge amounts of boost and only gets 0.2. WOT and across the whole rev range, well, at high revs to be clear. At low and medium it gets 0.1 or less.
Is has to be a very very large leak, from the exhaust or the intake.