A3 604 then BA 1458 at Heathrow
Athens → London → Edinburgh
Timetable, London time
17:55A3 604 from Athens at the gate
17:10BA 1458 to Edinburgh leaves the gate
23 h 15 apart on the timetable, overnight
BA 1458 leaves 23 h 15 after A3 604 arrives on the timetable: more than half a day, so not a connection we count.