FR 3977 then W9 5378 at Barcelona
Dublin → Barcelona → London Luton
Timetable, Barcelona time
21:10FR 3977 from Dublin at the gate
16:10W9 5378 to London Luton leaves the gate
19 h apart on the timetable, overnight
W9 5378 leaves 19 h after FR 3977 arrives on the timetable: more than half a day, so not a connection we count.