I first noticed this noise back in January, and it only seems to do it when the engine is cold.
You can only really hear it when in idle, and you blip the throttle. I've got a video clip where you can clearly hear it
Click here if you cannot see the above video...
If you start the video at 2:37, you'll be able to hear it when the revs drop.
I've checked all the hoses, and all are nice and secure, it's boosting fine, and no fault codes.
Engine is standard, apart from pre-cat pipe, which was only done 3 weeks ago, and I first noticed it 8 months ago.
Driven to work in it this morning, and it was doing it when I first set off, and had stopped by the time I got to work (6 miles away).
Any ideas/suggestions would be appreciated, as I've still got warranty on the car.
Also, found another thread which describes a sound in the exact circumstances as mine, and it doesn't sound like a turkey "gobbling"