BA 831 then BA 486 at Heathrow
Dublin → London → Barcelona
Timetable, London time
15:05BA 831 from Dublin at the gate
14:00BA 486 to Barcelona leaves the gate
22 h 55 apart on the timetable, overnight
BA 486 leaves 22 h 55 after BA 831 arrives on the timetable: more than half a day, so not a connection we count.