There is one aspect to this worth noting and that is that easyJet use a different dispute resolution service to BA. I often criticise CEDR, but the one thing they are quite focused on is "all reasonable measures". So at easyJet's intergalactic HQ they should have a full set of standby crew immediately available. There was a bit of weather and ATC delay yesterday, but this had largely gone by the time of the U2 flight (21:55 hrs) and was in any case manageable / within normal operational conditions. Still I would hope the OP looks at some CEDR rulings in the other thread and copies the language over to AviationADR who handle this for easyJet.

In particular I would want easyJet to clarify how this managed to happen, for an airline that does not have its intergalactic headoffice at Crawley International, who at least will not need to dole out any EC261 and for the right reasons: