BA 553 then BA 928 at Heathrow
Rome → London → Hannover
Timetable, London time
15:40BA 553 from Rome at the gate
14:50BA 928 to Hannover leaves the gate
23 h 10 apart on the timetable, overnight
BA 928 leaves 23 h 10 after BA 553 arrives on the timetable: more than half a day, so not a connection we count.