Getting a really weird rhythmic grinding / whirring sound. Don't notice it at speed and it's intermittent. Drove 2 hours today and it was really noisy at the end of the journey, coming back nothing at all until I was just about parked up, but not that noisy - and no sound 5 at all minutes before at some traffic lights. Don't think it's a trapped stone in the disks as it's still there when idling. Noise increases if I press the accelerator while in Park mode - doesn't seem to in neutral, but need to retest that next time it's noise - if I do, thinking of getting a garage to look at it asap. Any ideas on the cause?
Mk5 GTi, DSG. New belt a year ago, recent service and wheels aligned ok.