FR 10 then IB 723 at Madrid
Dublin → Madrid → London Heathrow
Timetable, Madrid time
21:15FR 10 from Dublin at the gate
16:45IB 723 to London Heathrow leaves the gatealso LA 1702, VY 5421, QR 6907, AA 8770
19 h 30 apart on the timetable, overnight
IB 723 leaves 19 h 30 after FR 10 arrives on the timetable: more than half a day, so not a connection we count.