FR 4596 then FR 8215 at Barcelona
Porto → Barcelona → London Stansted
Timetable, Barcelona time
22:15FR 4596 from Porto at the gate
19:10FR 8215 to London Stansted leaves the gate
20 h 55 apart on the timetable, overnight
FR 8215 leaves 20 h 55 after FR 4596 arrives on the timetable: more than half a day, so not a connection we count.