In a recent interview to air cargo world magazine, the UK and Ire head of EK cargo said that LHR, LGW and MAN would be all A380 by next summer (2/3 stages of that plan is now complete), that there would be a dedicated cargo flight to either MAN, LGW or STN, and that as most of EK's cargo is South East bound, London was the preffered option.
He also said that Until next year, cargo space on the B777's at BHX/GLA and NCL would be maxed out.
Given STN's superior cargo handling ability, my bets on STN.