FR 3976 then BA 831 at Dublin
Barcelona → Dublin → London Heathrow
Timetable, Dublin time
14:40FR 3976 from Barcelona at the gate
13:25BA 831 to London Heathrow leaves the gate
22 h 45 apart on the timetable, overnight
BA 831 leaves 22 h 45 after FR 3976 arrives on the timetable: more than half a day, so not a connection we count.