BA 1471 then BA 486 at Heathrow
Glasgow → London → Barcelona
Timetable, London time
10:15BA 1471 from Glasgow at the gate
16:10BA 486 to Barcelona leaves the gate
5 h 55 apart on the timetable
The last days
BA 1471 and BA 486 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.