Hi John
Agreed it is not related to engine revs but it also doesn’t occur when I go over bumps so I assumed it wasn’t suspension related either. It seems to occur when the car changes gear so in the audio file I am slowing down on the gears and the gearbox is progressively selecting a lower gear and I think it is when the gear change occurs that I get this sound. It also occurs when I start accelerating after slowing down so it could be the drive chain taking up some slack in the system or something.
Roger