Unfortunately I think this is how it is supposed to be working, and sometimes you can win, and sometimes you lose

First thing is a big assumption, that EF is actually showing real availability under the new system, which given its recent history I think is far from certain

So take a route, MAN- AMS next week on 8/10/25

Here is the view from EF based on individual flights and then based on married sectors. Note the higher availability for the MAN-AMS than both the MAN-LHR and LHR-AMS (R7 for example, and M9 L9 as well). So in this case BA seem to have decided to offer more availability than the individual flights. I think you can tell it is a married sector as it shows identical availability for both flights when looking at the MAN-AMS





Then let’s go MAN-IST instead. In this case BA has decided to offer less availability MAN-IST than one of the sectors. In fact they seem to have based the availability for the whole trip on the same availability as just the MAN-LHR sector. So if you have a flight booked in R MAN-LHR-XXX and you decided to change to MAN-LHR-IST you couldn't (ignoring the issue that the R fare itself might not be changable)







So two different routes on the same day, two different outcomes. I’ve also seen examples when they offer less on the married sectors than either of the two individual flights. Note there may well be other factors coming into play here, and maybe someone with more knowledge can comment. But the upshot is that for those of us that used to look at EF, see availability in the bucket we wanted, and think let’s go, life just became a bit more difficult