BA 867 then BA 420 at Heathrow
Budapest → London → Luxembourg
Timetable, London time
14:15BA 867 from Budapest at the gate
14:00BA 420 to Luxembourg leaves the gate
23 h 45 apart on the timetable, overnight
BA 420 leaves 23 h 45 after BA 867 arrives on the timetable: more than half a day, so not a connection we count.