BA 945 then BA 243 at Heathrow
Munich → London → Mexico City
Timetable, London time
12:55BA 945 from Munich at the gate
12:45BA 243 to Mexico City leaves the gate
23 h 50 apart on the timetable, overnight
BA 243 leaves 23 h 50 after BA 945 arrives on the timetable: more than half a day, so not a connection we count.