Originally Posted by
redshift27
I was about to give up (note that I could not simply "try" a dummy HKG-LHR booking because the error message occurred after payment details) when I had the idea of clicking the stopover option for the same day, and manually selecting the LHR-MAN flight. Bingo. Booked a minute later.
I had a similar problem and sorted it in the same way earlier this year. I was booking a flight back from NRT (MFU in to CW). When not adding the same day stopover there was no seat from NRT-MAN, yet when I did the same day stopover it came up even though I was just doing a normal 1-2hr transit at LHR and not really a stopover. Also, another trick is to do a 1 night stopover, but when you get in to the selecting flights page click back a day to get back to same day connection which sometimes then displays the flights.