EN 315 then BA 903 at Frankfurt
Firenze → Frankfurt am Main → London Heathrow
Timetable, Frankfurt am Main time
15:55EN 315 from Firenze at the gate
15:00BA 903 to London Heathrow leaves the gate
23 h 05 apart on the timetable, overnight
BA 903 leaves 23 h 05 after EN 315 arrives on the timetable: more than half a day, so not a connection we count.