DSG 'noise'

My Octy 2.0 TDi DSG went in last week to main dealer for the DSG oil and filter change. 

I drove it on my 100 mile commute and noticed that in 6th (possibly 5th too) that when accelerating there is a low frequency rumble/grind (probably a second on, a second off - not road speed) until I maintain speed. This doesn't happen in lower gears and speeds and the rest of the drive is flawless.

It was picked up that one inner and one outer driveshaft boot needed replacing. 

I know the answer is get it back to the dealer and that's what I'm going to do, but does anyone have any experience of this?