I have no doubt you are correct and I was probably given duff info!
I never saw a service booklet, but did get a copy of the drivers handbook (from the Briskoda forum) and on page 18 it refers to "The data displayed is the same after resetting the display with flexible service intervals (QG1) using the reset button as that for a vehicle with fixed service intervals (QG2)".
and on page 206 states "You can mix various oils together with each other when refilling with oil. This does not, however, apply for models with flexible service intervals (QG1)."
This intimates that some vehicles do in fact have flexible service intervals, along with the info given to me that cars with maxidot info screens had flexible service intervals I was under the impression that the Fabia Elegance 105bhp CR 1.6 TDi had flexible intervals. However as I never bought the car due to the problems with delivery dates, I am not in a position to doubt that what you say is true.
many thanks