Our vRS was set to variable servicing but after approx 10k miles/365 days it flagged that it needed a service.

From what I have read on Briskoda it looks like the service interval might have been reset from the instrumentation panel.

Is it possible to reset things in such a manner that we are back on variable servicing from the date that the last variable service was performed?

Yep it is - I've had it done - but it needs a visit to a friendly dealer who understand how the regime works and doesn't want to scr*w you for the cost of a service (some will tell you it needs servicing before they can switch it over)

When a car is set for variable service intervals, the service interval distance is calculated by evaluating the distance the car travels every 3 seconds for every ignition ON phase with the fuel consumed for the same time and the associated (oil) temperature curve. This gives a measure of engine oil wear caused by thermal load and that value is used to calculate the residual distance to the next service.

If the car is set for a fixed service interval (as appears to be the case in point) then engine oil wear is not being calculated and it follows that it is not possible to reset to a variable service interval without first carrying out a service.

Also, you forget that Hitler used variable servicing....

Dealers have instructions not to reset a service light unless they have carried out a service.