QR 3663 then BA 483 at Barcelona
Bologna → Barcelona → London Heathrow
Timetable, Barcelona time
10:05QR 3663 from Bologna at the gatealso LA 5855
15:30BA 483 to London Heathrow leaves the gatealso IB 3780, AY 5938, QR 5984, AA 7061, VY 9561
5 h 25 apart on the timetable
The last days
QR 3663 and BA 483 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.