BA 971 then BA 752 at Heathrow
Hamburg → London → Geneva
Timetable, London time
07:30BA 971 from Hamburg at the gate
19:25BA 752 to Geneva leaves the gate
11 h 55 apart on the timetable
The last days
BA 971 and BA 752 weren’t both flown 15 min to 12 h apart in the last 21 days.
Statistics from past flights, not live flight information. Always check times and your connection with your airline, and don’t base travel or booking decisions on these numbers.