DSG Power Cuts Out over 5000rpm in Sport

[BenBA4]

Hi,

My 08 Passat CC VR6 has a DSG issue but only in Sport.
When the revs pass 5000 it cuts out completely, the revs drop and the accelerator does nothing (engine and electrics still on)
However if I switch back into Drive it works fine again like nothing was wrong

There are no other DSG warning signs, it’s not clunky and has no issues at lower revs or at all in Drive.
There are no DSG warning on the dash and the engine is always up to temp before WOT.

Has anyone got an idea of what it could be or seen this before?

Just in case it’s relevant, it had a new battery and alternator before Xmas and has barely been driven since due to lockdown.

Thanks for any pointers
Ben

Edit: just scanned it and it is throwing up P0321.
Maybe speed sensor?