FR 7595 then A3 604 at Athens
Budapest → Athens → London Heathrow
Timetable, Athens time
00:30FR 7595 from Budapest at the gate
15:55A3 604 to London Heathrow leaves the gate
15 h 25 apart on the timetable
A3 604 leaves 15 h 25 after FR 7595 arrives on the timetable: more than half a day, so not a connection we count.