Help!!!

I've just replaced my original T34 with a brand new T34 with a 360 bearing and it doesn't seem to be producing enough boost. The car is on a stage 3 setup and was originally holding ~25 PSI before the turbo died.

On the first run out I couldn't get much more than 12PSI out of it so I changed the actuator for my old -31.
With it set as it had come off the old turbo I managed 14PSI. Tightened the rod and managed 15PSI. Contacted the turbo people and they sent me a -34 FOC which I installed. Initially it was holding 15PSI and 4 - 5 full turns of the actuator rod later, I am now holding 17PSI- with a -34!
I have put a compressor onto the actuator and I have a maximum of 5mm extension (no idea what pressure it starts moving, will get a regulator/ gauge and confirm tomorrow)- it seems I have very nearly forced the wastegate to be permanently closed.

Checked the intercooler for signs of a hole- as I had very similar symptoms once before and found a gaping split in the intercooler. I've checked the boost hoses and they are OK. Tried a different dump valve and lastly sprayed ez start over the intercooler and all boost hose joints in hope of identifying a leak/ hole., without success.

Run out of ideas, any suggestions before I take the turbo off and return it again????

Cheers!!