BA 893 then BA 199 at Heathrow
Sofia → London → Mumbai
Timetable, London time
22:30BA 893 from Sofia at the gate
20:15BA 199 to Mumbai leaves the gate
21 h 45 apart on the timetable, overnight
BA 199 leaves 21 h 45 after BA 893 arrives on the timetable: more than half a day, so not a connection we count.