update:
done a propper boost leak test today.
removed air filter & blocked off. put a tyre valve to the intake manifold. had a compresser, filled the engine to aroun 0.5Bar (thats all it would hold)
put soapy water around all the IC pipes, dv, all fine. put some over where the throttle body connects to the intake manifold, leaking there
also leaking where the intake manifold connects to the runners, and where the idle valve connects to the intake manifold.
this is because i have had all the manifold off recently, to clean & paint it up.
PS no air was leaking where the duck tape covered the dv return pipe. wil get a nice rubber one though.
i will admit now the ferris beuler method woudnt have been pritty dumb
glad i know where the leak is from, i re-used the existing metal gaskets, is this the reason why its leaking air? or have i not got the manifold sitting/tightened unevenly?