Looking at flight aware Thomas cook Gatwick to dalaman flights the history for the past 4 weeks show that Almost All flights on this route have long delays 2 hrs to 29 hours or cancelled flights seems that Thomas cook have major problems on this route keeping to flight times, it also shows NOT due to Tec problems but flight take off spots.i cant see them lasting on this route,
pity jet 2 don't fly from Gatwick or more easy jet flights, or dare I say it Ryan air or Norwegian.
routes from other airports look pretty good.
Pompeylee I hope your family/ friends hits them hard with compensation claims best template is on martin lewis web site