Naughtie

Other vehicle allow me to close the power liftgate from the drivers seat, using the same switch I open it with.

Not the allroad.

Is there a workaround to allow me to close it from inside the cabin?

It sounds petty (actually, it is petty), but I drive through a security checkpoint at work, and if my cargo cover isn't open, I get a free inspection. Most of the guards know what's up, but there are a few -- and one who's a bit short -- requiring me to unbuckle, get out to close it, hold up the queue, etc.

Is there a Vag Com setting for this?

TREGinginCO

Not that I'm aware of.