The main issue was that the charge only applied once the driver exited the Upper Wing as the only way to exit is to drive through the drop-off charge zone which I guess is why VS have been able to negotiate with HAL to waive the drop-off charge for the Upper Class Wing.
That linked VS webpage does also actually contradict itself:
Driving directions to the Upper Class Wing
Where to find us
When you arrive at London Heathrow, ask your driver to turn left before the usual T3 drop off location, following the 'Virgin Upper Class Wing' sign.
At the top of the ramp, ask your driver to park in one of the bays, We’ll meet you there and see you on your way to the Clubhouse.
Exit as normal through the Terminal 3 forecourt. ANPR cameras will register your vehicle and automatically exempt the fee.
The Heathrow Airport Terminal Drop Off Charge does apply to The Upper Class Wing.
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