Sometimes when changing gear quickly from first to second after really giving it some (front wheels still spinning) when i engage second and floor it again, the car feels very hesitant, like the wastegate is still open or something and will just pop, bang & have no power.
It has no power although the boost gauge can read anything up to about 30psi as if the turbo is spooling, but the pressure is going somewhere else

This is not the easiest thing to explain, but that's the best i can do. No fault codes, and when i leave throttle for a second and put foot back down it will boost back up and carry on normally, leading me to believe there are no leaks or anything anywhere.
It seems as if it only does this when i change gear and the front wheels are actually spinning while changing

My initial thoughts are the wastegate, N75, or 007p not operating fast enough? but how the hell do i check these?