Trying to book a round trip BWI-CAI (business, British Airways) and ran into an issue. Any help out there?

Hello!

Am trying to book this roundtrip flight from Baltimore-Cairo (w/layover in London) this August 5-16 on business class with British Airways.

On Google Flights found the perfect flight: BWI-CAI #BA397 7:25PM-5:25PM (leaving the 4th,landing the 5th)

CAI-BWI #BA229 6:20PM-7:45PM (leaving the 15th, landing the 16th) Legs as follows: -CAI-LHR 6:20pm-9:35pm (overnight stay in London) -LHR-BWI 12:25pm-3:50pm (leaving on the 16th)

When I went to book it though the BA website, there is no return flight #229 to BWI. There is only a flight to Dulles (which we are trying to avoid). There is an earlier flight to BWI but we need the departing Cairo @6:20pm one (or anytime after 1pm).

I've submitted a request to BA via their help form but haven't heard back yet. Would anyone know why this is happening?

Thanks for any advice or input!