FR 339 then FR 3568 at Dublin
London Luton → Dublin → Santiago de Compostela
Timetable, Dublin time
20:30FR 339 from London Luton at the gate
18:50FR 3568 to Santiago de Compostela leaves the gate
22 h 20 apart on the timetable, overnight
FR 3568 leaves 22 h 20 after FR 339 arrives on the timetable: more than half a day, so not a connection we count.