QR 3733 then W9 5378 at Barcelona
Mahón → Barcelona → London Luton
Timetable, Barcelona time
19:25QR 3733 from Mahón at the gate
16:10W9 5378 to London Luton leaves the gate
20 h 45 apart on the timetable, overnight
W9 5378 leaves 20 h 45 after QR 3733 arrives on the timetable: more than half a day, so not a connection we count.