Well I had a read of the instructions and got the car back out.
I bypassed the boost controller solenoid so that the actuator was providing full control and went for a pootle. It peaked and held pretty steady at 12.6 before slowly tapering off to 10.9
I'm just accepting that the actuator is preloaded to 12.6 psi and as it's such a pain in the ar$e to adjust I'm just gonna leave it at that.
So i reconnected the boost solenoid and preset it as follows.
Channel 1- 10 duty 0 gain result 11.9
Channel 2- 20 duty 0 gain result 12.4
Channel 3- 30 duty 0 gain result 14
Channel 4- 40 duty 0 gain result 18.1
Channel 5- 50 duty 0 gain result 20.8
Channel 6- 53 duty 0 gain result 22.1
All the above were dropping off t0 12/13psi
So I stuck with channel 6 and started upping the gain
at 10 gain it dropped to 14psi at 20 it dropped to 15psi and when turned up to 30 it was hovering around 16psi.
So it looks as though we've finally got to the bottom of the problem.
It's booked in for mapping on Fri so will get the mapper to have a bit of experiment when its on the rollers. I'll probably settle for something like 40 duty and maybe something in the region of 40 gain. This should hopefully see a smoother boost curve which is held all the way through the rev range, as to be honest with 22psi it comes in with quite a bang.
Obviously having 6 channels I might retain one as my "german car tormentor" setting for those dual carriage way blats (you know the one when some one pulls out of the fast lane then puts there foot down so you can't get passed).
Anyway thanks to everyone who helped me out with more so Mart and Andrew who were both on the button with the actuator being incorrectly preloaded and the boost controller no set up correctly.
I'll let you know what it make on fri but it's been pretty consistant with 260 at 12psi so should (fingers crosed) make a little bit more.