I checked on expertflyer some random dates you mentioned above. The flights I checked the availability for fare classes are very strange.
So for example on the 23/02/2020 BA2644 looks like this.
J9 C4 D0 R0 I0 Y9 B0 H0 K0 M0 L0 V0N0 O0 Q0 S0 G0
So basically BA only sell in Economy a fully flexible tickets, CE similar you too. Seat maps however show all seats available to select.
Most likely this is an unintentional and unrealistic sale configuration for these flights.
I would wait at least a couple of days and hopefully someone in Revenue management will correct this to a more reasonable figures. I don't think they will find over a 100 people to pay full flex economy tickets every day for these flights.