EC 3749 then IB 5408 at Barcelona
Milan → Barcelona → London Gatwick
Timetable, Barcelona time
21:30EC 3749 from Milan at the gate
13:25IB 5408 to London Gatwick leaves the gatealso LL 5408, VY 7612
15 h 55 apart on the timetable, overnight
IB 5408 leaves 15 h 55 after EC 3749 arrives on the timetable: more than half a day, so not a connection we count.