EasyJet today flies from four London airports. The only airport I see the word "move" can be used is at STN - in the the sense of "move from". For the three other airports the proper word would be "add" - as in add frequencies or add destinations. An opening at LHR the proper word again will be "add" - as in add service. I do think U2 flights in to LHR may "steal" passengers from their LTN and BRS operation more than from LGW, but the real losers will be the legacy carriers that have put all their eggs in to one London basket - at LHR.