Disconnect all the vac lines from the ext/wastegate, and run a single line from the turbo to the bottom port of the ext wastegate and see what it will do.
Not quite sure how that's been plumbed in, but it doesn't look right although maybe it's a little difficult to tell from the photo.
Using one length of hose, connect the side port of the wastegate to the nipple on the compressor housing of the turbo, leave the other port on the wastegate open to atmosphere. With the wastegate setup like this, boost pressure will be regulated by the spring pressure that's in the wastegate.
If the turbo still over boosts then you need to check the wastegate i.e. remove it and strip it apart.
I had the blitz ebc, had the same problem, kind of narrowed it down to the solenoid being fcuked, and to replace the solenoid you could pick up a second hand one, or for a little more an avcr, I just chucked it in the bin.
Is yours brand new?
If you have a 0.7 bar spring in the external wastegate, then yes you have a problem with the electronic boost controller somewhere.
If your unsure what spring you have tou can just undo the top of the wastegate, they are coloured, i'm sure i've seen tial have a chart somewhere as to what colour gives what pressures. If your colour matches to the 0.7 bar then the ebc is causing you problems.
It sounds as if you have set it up right so that kind of narrows it down.
Do you have the dual solenoid type or the single solenoid type? Not sure what they are on the ID versions.
I think the dual solenoid was about £140 if I remember rightly, brand new.
I'd be surprised if the solenoid has just packed up like that. I would be connecting it all back up as it should be, double check the SBC settings and try it again.
well ive been thinking maybe it hasnt worked ever since ive had it i didnt hit boost till late, when i first had it was getting up to boost around 6grand maybe ive came up to 1.2 but never gone over coz ran out of revs ive now sorted that a little by welding the old actuator bracket shut. Now im overboosting maybe this is because i now hit boost quicker therefor have more revs and goes past 1.2 there for the screamer pipe wouldnt work because the ebc isnt telling the ewg that its hit full boost and opening the ewg up , so when i changed it round to just running on the spring on the ewg the noise i heard was the screamer pipe, maybe the solenoid has been broken since ive had it ?