Not a surprise really. The base never ever made a positive contribution to easyJet results. They should not have opened it at the first place...
Low costs at network carriers hub rarely make money (except U2 at CDG because of AIRFRANCE non sense, or Ryanair at DUB vs. a previously very weak EI), contrary when entering rich secondary cities (GVA, MIL, BCN, BER etc). Plus low yield market, plus most competitive hub airport in Europe with Ryanair AND easyJet plus IB express and Vueling, plus internal mistakes (some ridiculous routes such as BOD, SOF, or OTP; bad revenue management with all their VFR or summer only routes always sold out 2 weeks before departure), plus the environment (e.g. arab spring killed their good morocan routes), plus future taxes increase etc etc
Re-SEN, they won't switch aircraft from underperforming bases to underperforming bases. It will go to their good countries where competition is weak and corporate demand strong i.e. France (probably 3 or 4 ac), Italy (2) and Swiss (1 each for BSL/GVA). I doubt the UK will get any.