**UPDATE**
I just took the car for a 10 mile drive to see if it was any better and it isn't

In third gear I can slowly build the boost and revs but as soon as it gets to about .7 bar it starts slipping

That is obviously on part throttle so it can't be making much power or torque
When the clutch was fitted the ratchet should have been reset as soon as it was reconnected and used but the pedal still feels high, could there be an issue with this and do they go wrong?
Your input is appreciated because I'm confused how it can be this bad.
Thanks,
Paul