BA 483 then BA 822 at Heathrow
Barcelona → London → Billund
Timetable, London time
19:25BA 483 from Barcelona at the gate
16:05BA 822 to Billund leaves the gate
20 h 40 apart on the timetable, overnight
BA 822 leaves 20 h 40 after BA 483 arrives on the timetable: more than half a day, so not a connection we count.