This is quite a timely resurrection of this thread as I've also been having noise from the engine bay, which I previously thought was an exhaust problem.
I have the 1.4 16v engine, so they layout is slightly different but my air intake still attaches to a metal bracket with a rubber mounting. It's always been a bit loose, but I cable tied it and the noise seems to have gone away (need to go for a longer test drive to confirm).
Anyone know what the right part number is for the 16v engine? I think it's part 5 in the diagram ("Bracket" 51775002), which seems to be the bracket with mounting pre-attached. Is something that attaches to the air intake pipe needed (picture with part circled)?