And how can splitting a route (with or without a change of route number) without a change of vehicle avoid the need to use a tachograph?
I'm thinking of the Newcastle-Carlisle route 685.
Stagecoach 'changes' at Brampton whilst Arriva 'changes' at Haydon Bridge.
Passengers are through-ticketed and there is no change of vehicle - merely an alteration of the destination blind.
(or is this impossible to explain?)