FR 3976 then FR 120 at Dublin
Barcelona → Dublin → London Gatwick
Timetable, Dublin time
23:30FR 3976 from Barcelona at the gate
16:55FR 120 to London Gatwick leaves the gate
17 h 25 apart on the timetable, overnight
FR 120 leaves 17 h 25 after FR 3976 arrives on the timetable: more than half a day, so not a connection we count.