FR 3881 then BA 837 at Dublin
Dubrovnik → Dublin → London Heathrow
Timetable, Dublin time
23:05FR 3881 from Dubrovnik at the gate
19:25BA 837 to London Heathrow leaves the gate
20 h 20 apart on the timetable, overnight
BA 837 leaves 20 h 20 after FR 3881 arrives on the timetable: more than half a day, so not a connection we count.