Over the past few summers there's been virtually no spare capacity for aircraft parking, especially during the night/early hours when all the TCX, TOM, LS, EZY, FR etc were back home before the first wave. Pissing off the majority of your airport users to accommodate a 3x weekly 744F freighter (which barely brings any revenue into the airport compared to passengers) doesn't make business sense. They're more hassle than they're worth at an airport that's already filled to the brim.