BA 1485 then BA 426 at Heathrow
Glasgow → London → Luxembourg
Timetable, London time
19:00BA 1485 from Glasgow at the gate
18:45BA 426 to Luxembourg leaves the gate
23 h 45 apart on the timetable, overnight
BA 426 leaves 23 h 45 after BA 1485 arrives on the timetable: more than half a day, so not a connection we count.