FR 6927 then W4 6003 at Fiumicino
Barcelona → Rome → London Luton
Timetable, Rome time
18:40FR 6927 from Barcelona at the gate
12:10W4 6003 to London Luton leaves the gate
17 h 30 apart on the timetable, overnight
W4 6003 leaves 17 h 30 after FR 6927 arrives on the timetable: more than half a day, so not a connection we count.