We booked a holiday in Portugal with a tour operator we’ve used before. This time they keep making last-minute adjustments to schedules and have brought our Heathrow flight forward by six hours, which ended up costing our party an extra £370 in order to get there on time. The alternative would have been to forgo the holiday.
It’s more than likely that the tour operator will reserve the right to alter flight times and the like in the small print on your ticket. That being the case your only recourse is to complain vociferously when it happens, and let them know that your future custom is in jeopardy. It’s possible of course that such arrangements are outside the tour operator’s control, but if you complain enough they may at least be persuaded to give you a discount off your next holiday.