BJ 246 then BA 903 at Frankfurt
Tunis → Frankfurt am Main → London Heathrow
Timetable, Frankfurt am Main time
17:05BJ 246 from Tunis at the gate
16:40BA 903 to London Heathrow leaves the gate
23 h 35 apart on the timetable, overnight
BA 903 leaves 23 h 35 after BJ 246 arrives on the timetable: more than half a day, so not a connection we count.