OS 335 then BA 584 at Heathrow
Vienna → London → Milan Linate
Timetable, London time
14:05OS 335 from Vienna at the gate
13:15BA 584 to Milan Linate leaves the gate
23 h 10 apart on the timetable, overnight
BA 584 leaves 23 h 10 after OS 335 arrives on the timetable: more than half a day, so not a connection we count.