BA 941 then BA 800 at Heathrow
Düsseldorf → London → Reykjavík
Timetable, London time
07:45BA 941 from Düsseldorf at the gate
07:35BA 800 to Reykjavík leaves the gate
23 h 50 apart on the timetable, overnight
BA 800 leaves 23 h 50 after BA 941 arrives on the timetable: more than half a day, so not a connection we count.