Now I'm worried. I booked flights on BA to travel from Toronto to New York (AA) and onto Heathrow (BA) on 26 December. I always do OLCI but if I am reading the above responses correctly, I won't be able to obtain BP's for our flight from JFK to LHR when I check in on Christmas Day as it is two different airlines although all part of One World. It's difficult enough to clear customs in Toronto - now we have to worry about whether or not we can obtain BP's for the whole trip? And here I was worried about my British spouse having to wait hours for me to clear "Non-EU" customs when we lat Heathrow and possibly miss our BA flight to Edinburgh (for which I allowed five hours).

Do I panic now or later?