Mention that you are aware of other people having the same problem with their cars and that in some cases it has been caused by a collapsing hose. It might just jog the dealer into checking for that if they can't find the source of the problem and have run out of ideas.

Cleaning the throttle body is apparenlty something that Skoda recommend for surging having spoken with a mechanic at my local dealer. If this cures the problem, expect the thing to need cleaning after a few thousand miles. After 2 or 3 cleans Skoda will sanction a new throttle body if pushed.

Phil