BA 673 then SK 534 at Heathrow
Thessaloniki → London → Stockholm
Timetable, London time
21:45BA 673 from Thessaloniki at the gate
21:05SK 534 to Stockholm leaves the gate
23 h 20 apart on the timetable, overnight
SK 534 leaves 23 h 20 after BA 673 arrives on the timetable: more than half a day, so not a connection we count.