pop the intercooler off and look for ally shavings, failing that it sounds like a loose turbo sheild.

Thanks for the responses. Was in a hurry to get that sorted as I was on my way out the door for a drive to the snow (1000km round trip). Ended up getting a stethoscope thingo onto it and identified the noise source as indeed being a heatshield. Started at the RHS manifold and found a busted lug on the upper shield. Panic stations abandoned. Now to fix it.. ..

Pondering this at work (car is 75km away farkin). .. . .

Can I get that upper manifold shield off without removing the manifold from the head? Quick feel around last night suggested there's a bolt on the side that should be easy enough to get to, but the other 2 on top might be tricky.