BA 673 then VY 7643 at Heathrow
Thessaloniki → London → Barcelona
Timetable, London time
21:45BA 673 from Thessaloniki at the gate
20:50VY 7643 to Barcelona leaves the gate
23 h 05 apart on the timetable, overnight
VY 7643 leaves 23 h 05 after BA 673 arrives on the timetable: more than half a day, so not a connection we count.