I have fixed the whistling noise!!!!!

I started buy spraying carb cleaning around the inlet to throttle gasket but nothing, then tried all the pipes to throttle with carb cleaner and nothing. spray carb cleaner around the idle screw and still no change. I took the piping off for aux air valve and bypassed it and still no cure the noise was still there.

Stripped the throttle body off again and inspected the surfaces for sign of a leak but nothing (they were smooth no lumps or bumps of old gasket ). Did the same for the surface to the inlet and nothing there.

So cleaned the surface of the inlet and the throttle body with fine wet and dry and then re-assembled the throttle but this time using a smear of blue ford gasket sealer. Took idle screw out and put a smear of oil on threads.

Run it up and set the idle again and take it out and NO WHISLTE NOISE

Cheers for everyones thoughts and advice