VS 355 then BA 588 at Heathrow
Mumbai → London → Milan
Timetable, London time
15:40VS 355 from Mumbai at the gate
15:20BA 588 to Milan leaves the gate
23 h 40 apart on the timetable, overnight
BA 588 leaves 23 h 40 after VS 355 arrives on the timetable: more than half a day, so not a connection we count.