annoying short sharp whistle noise has started lately same rev range only when driving not stationary.I know what the usual spool up noises are etc this is something else.any help appreciated

Might be a boost leak, is it louder when under load over a constant throttle 

No its exactly the same its only over about 300 revs I can play with throttle and keep it going but if I accelerate hard it goes away .its just annoying ive checked all pipes except turbo as its lowered and I cant get it on ramps