I had previously opened a ticket with EF who acted as if it was something they didn't know about already. Needless to say there has been zero feedback on my ticket or change to the situation.

There are 2 issues:
1. Seat maps not available from when check-in opens (T-24 hours)
2. Blocked seats always show as if occupied. This is for all BA flights, not just from T-24.

Issue 1 also exists for LH Group flights from T-48 but in that case only for Economy. The seat map for Business is still visible. I have a feeling this might be to do with the BA migration from FLY to another Amadeus solution.