FYI this seems to be a broader issue and ba.com specific. I.e. a problem with BA's website. As such ideally a moderator would move this to the BA forum.

Prompted by noting that whilst a few days ago HKG-LHR award bookings on CX in economy was widerly available most or all days this and next week on ba.com, now it's only showing available from Oct 27th onwards (suspisciously a week away) BUT availability is still showong on aa.com for every day from today till at least Oct 29th I assume it's also available if you call BA rather than rely on their broken website given that worked for HKG-DPS.