Hello and welcome to just answer
It sounds very much like you have a problem with the turbo becoming sticky. These run a variable vane turbo and they can get full of carbon build up which causes the little vanes to stick. They tend to stick in the full turbo position as that part is rarely used except when you are using the engine to go up hill or pull away really quickly.
When you turn the engine off the actuator on the turbo then pulls the vanes free and you are up and running again as before and works fine unitl you use the higher boost on the turbo.
Innotec-world.com offer a cleaning set which has been designed to be used on these turbos to help remove the carbon build up.
I hope this helps and if I can help further please feel free to ask
Hi thank you for that.
Have you ever had the fault memory checked for the engine ecu and if so so you remember what codes if any that were stored in it please?