Originally Posted by
number_6
..MA is difficult to deal with for complex ticketing (they aren't used to it) so you may have to use a travel agent in BUD though there is likely to be a Hungarian TA in London who can arrange things for you (maybe even be able to issue MA ticket with LHR origination). ...
Might be extra hard as TA has to queue the booking to the airline with the first transoceanic route who will then be pricing the fare, fuel surcharges and all.
So unless you actually fly with MA as your first transatlantic segment, its gonna be hard to get it priced properly.