FR 8385 then FR 8217 at Barcelona
Budapest → Barcelona → London Stansted
Timetable, Barcelona time
11:35FR 8385 from Budapest at the gate
09:00FR 8217 to London Stansted leaves the gate
21 h 25 apart on the timetable, overnight
FR 8217 leaves 21 h 25 after FR 8385 arrives on the timetable: more than half a day, so not a connection we count.