BA 1497 then BA 496 at Heathrow
Glasgow → London → Barcelona
Timetable, London time
07:15BA 1497 from Glasgow at the gate
19:20BA 496 to Barcelona leaves the gate
12 h 05 apart on the timetable
BA 496 leaves 12 h 05 after BA 1497 arrives on the timetable: more than half a day, so not a connection we count.