BA 483 then BA 512 at Heathrow
Barcelona → London → Lisbon
Timetable, London time
19:25BA 483 from Barcelona at the gate
18:55BA 512 to Lisbon leaves the gate
23 h 30 apart on the timetable, overnight
BA 512 leaves 23 h 30 after BA 483 arrives on the timetable: more than half a day, so not a connection we count.