BA 965 then BA 588 at Heathrow
Hamburg → London → Milan
Timetable, London time
21:30BA 965 from Hamburg at the gate
16:55BA 588 to Milan leaves the gate
19 h 25 apart on the timetable, overnight
BA 588 leaves 19 h 25 after BA 965 arrives on the timetable: more than half a day, so not a connection we count.