May be, but knowing Thomson /Tui /Britannia over the years, they tend to be / can be very switched on. With their current 'European TUI Fleet', and they,as a group (TUI) looking at current loads, especially at the short haul market, where they may have L/H aircraft aircraft pre - allocated, I am sure they will be doing their very best to utilise their current fleet, - where perhaps their current loads may be poor / slow - and perhaps downgrade for a month or so,on certain routes to meet their potentially initial 'problem'. Lets remember, April & early May, can be slow, so they may have opportunities, to put in place a damage limitation exercise to cover the spring time.Hopefully the 787 issues may then be resolved.
Costs though down to Boeing -I think so, because surely ,sadly, they are liable?