IB 5423 then QR 3602 at Barcelona
London Heathrow → Barcelona → Rome
Timetable, Barcelona time
13:10IB 5423 from London Heathrow at the gatealso LL 5423, VY 7641
12:30QR 3602 to Rome leaves the gate
23 h 20 apart on the timetable, overnight
QR 3602 leaves 23 h 20 after IB 5423 arrives on the timetable: more than half a day, so not a connection we count.