FR 2972 then FR 337 at Dublin
Kaunas → Dublin → London Luton
Timetable, Dublin time
23:10FR 2972 from Kaunas at the gate
17:45FR 337 to London Luton leaves the gate
18 h 35 apart on the timetable, overnight
FR 337 leaves 18 h 35 after FR 2972 arrives on the timetable: more than half a day, so not a connection we count.