No joy in finding the screech yet. So far I've fitted egr delete kit, decat(knocked the insides out) and given the car a service because it didn't look like it had been done in a while.
Fitting the egr delete has made the screech sound louder. Also cleaned the turbo with mr muscle whilst the cat was off. I've done a boost leak test on all the pipe work including intercooler.

When driving the screech sounds as tho it's coming from the turbo area of the car. It's starts at 2500 rpm and fades away about 4000 rpm. If u give it a hard rev when stationary u can just hear a screech.

Running out of ideas now other than replacing the turbo