FR 3801 then BA 483 at Barcelona
Birmingham (UK) → Barcelona → London Heathrow
Timetable, Barcelona time
20:50FR 3801 from Birmingham (UK) at the gate
15:30BA 483 to London Heathrow leaves the gate
18 h 40 apart on the timetable, overnight
BA 483 leaves 18 h 40 after FR 3801 arrives on the timetable: more than half a day, so not a connection we count.