Colour me confused, what pulley ratio are you running?

Mine is 2 dead (120 & 60), and peak at about 160kpa with a VVT engine

Can you disconnect the VICS solenoid and report back?

Sure can Dimitris.

How is best to disconnect it? Pull and plug the vac line or disconnect the electrical connector? My head says the connector, but I'm unsure of the rest position of the butterfly's.

Just pull the connector.

Okay tried on the way home and pulled what I thought was the VICs connector (2 pin connector at the rear of the intake with a small vacuum pipe next to it)

The problem is still apparent, I hit 12.5psi and my boost gauge hit ~10psi. My pulleys are 65/110.

Did I disconnect the correct connector for VICs? I pulled the one circled on the left. There is one above that with what looks like there are 3 pins to it, but it was dark and 0*C outside so I didn't hang about.
Attachment 192482

Halp!

Looks like the one, although the solenoid is a 2 pin connector.

that connector on the left is for EGR isn't it?

VICS actuator is the item circled on the right.

I don't think there is an electrical connector in the region of the actual actuator circled on the right Richy?

How else can I be sure I'm 100% completely disconnecting VICs - pulling and plugging the vacuum line?

If I had a partially blocked CAT or restriction in the exhaust then that would likely produce a slow build up of boost as the back-pressure rises with increased RPM. Another suggestion has been a sticking valve but surely that would represent itself in a similar fashion to a blocked exhaust and not manifest itself as on/off at 6krpm every time?