FR 155 then U2 2306 at Madrid
Bristol → Madrid → London Luton
Timetable, Madrid time
13:00FR 155 from Bristol at the gate
11:00U2 2306 to London Luton leaves the gate
22 h apart on the timetable, overnight
U2 2306 leaves 22 h after FR 155 arrives on the timetable: more than half a day, so not a connection we count.