I very recently UuA'd a WT+ to CW LHR - JFK return trip for two, and it came to a difference of about £240 total, so about £120 each. Annoyingly, had made the booking over the phone and was told about £70 each and when it was booked was then told it was more than expected. Not that it would have stopped me booking it but still prefer to know what I'm paying before the booking is made.