BA 923 then BA 868 at Heathrow
Hannover → London → Budapest
Timetable, London time
13:10BA 923 from Hannover at the gate
13:00BA 868 to Budapest leaves the gate
23 h 50 apart on the timetable, overnight
BA 868 leaves 23 h 50 after BA 923 arrives on the timetable: more than half a day, so not a connection we count.