FR 667 then FR 373 at Dublin
Birmingham (UK) → Dublin → London Luton
Timetable, Dublin time
14:55FR 667 from Birmingham (UK) at the gate
11:15FR 373 to London Luton leaves the gate
20 h 20 apart on the timetable, overnight
FR 373 leaves 20 h 20 after FR 667 arrives on the timetable: more than half a day, so not a connection we count.