FR 6921 then U2 2324 at Barcelona
Dublin → Barcelona → London Luton
Timetable, Barcelona time
12:00FR 6921 from Dublin at the gate
10:25U2 2324 to London Luton leaves the gate
22 h 25 apart on the timetable, overnight
U2 2324 leaves 22 h 25 after FR 6921 arrives on the timetable: more than half a day, so not a connection we count.