Moderator, Iberia Airlines, Airport Lounges, and Ambassador, British Airways Executive Club
Join Date: Feb 2010
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1) You should be eligible for downgrade reimbursement using the Mennens formula, which is linked in to the Wiki of this thread. BA also have their own refund formula, but with the UuA aspect I'm not sure how that would work. In your shoes I would do a back of the envelope calculation of that, ascribing a value to the Avios of for example 1.5p per Avios, and adding to the CW fare. Then either ask for that specifically, or compare it to whatever BA offer. This may take some time (a few weeks).
2) The two delayed to SEA sound like they are in scope for the 600€ delay payment, depending on exact timings.
3) For the others downgrades, same as reply 1 except that being revenue they may find BA's offer is more attractive, depending on the precise fare involved.
Right to care (etc) applies throughout for meals and hotel, so no issue there as far as I can tell.