FR 9754 then FR 731 at Vienna
Banja Luka → Vienna → London Stansted
Timetable, Vienna time
14:30FR 9754 from Banja Luka at the gate
13:15FR 731 to London Stansted leaves the gate
22 h 45 apart on the timetable, overnight
FR 731 leaves 22 h 45 after FR 9754 arrives on the timetable: more than half a day, so not a connection we count.