Vauxhall astra 2l turbo limp mode help

[BAM5306]

I got a 05 vauxhall astra 2l turbo petrol and I'm having trouble with limp mode coming on at different times on journeys I have had it checked it comes up with accelerator pedal so changed that now it says solinoid valve but I think it is the lamba sensor in exhaust anyone with ideas

[Locknut]

If you switch off and restart the car does it revert to normal until the next time?

If so, I would suspect sticking turbo vanes causing over-boost but that should log a fault code.