Whilst driving to work, on the approach to a roundabout, I heard what sounded like the compressor in the boot running, but slower.
Upon accelerating after the roundabout, I could hear a whooshing sound from the car which I though initially was the turbo. Its not down on power, but the whoosh steps down when I slow down, so I think its transmission related. I also tried freewheeling in the works car park and the whoosh stopped.

I'm hoping the transmission isn't foooked