FR 341 then FR 3977 at Dublin
London Luton → Dublin → Barcelona
Timetable, Dublin time
10:00FR 341 from London Luton at the gate
08:50FR 3977 to Barcelona leaves the gate
22 h 50 apart on the timetable, overnight
FR 3977 leaves 22 h 50 after FR 341 arrives on the timetable: more than half a day, so not a connection we count.