I'm puzzled - why do we choose mainland Europe airports when NCL, EDI etc. are open - it'd be much easier to coach from there than face the channel crossing?
BA look at the bigger picture.....they may be already have crews available in those airports that are able to get the aircraft out again....
there may be a longer "window" to get their aircraft away again....
they don't want aircraft stuck anywhere when they can depart and it is still relatively simple to get their pax back from Brussels for example.