QR 3641 then BA 481 at Barcelona
Catania → Barcelona → London Heathrow
Timetable, Barcelona time
20:55QR 3641 from Catania at the gate
14:40BA 481 to London Heathrow leaves the gatealso IB 3663, AA 6819, VY 9559, QR 9800
17 h 45 apart on the timetable, overnight
BA 481 leaves 17 h 45 after QR 3641 arrives on the timetable: more than half a day, so not a connection we count.