BA can certainly release seats in any class as flight nears.

BA certainly will not release 'any unsold seats' in any class.

In short, redemption buckets work just like any other bucket (apart from the guaranteed release on day 1 for a number of J and Y seats). Depending on loads and yield, revenue management may or may not increase or lower availability in any given bucket, so now there is F2 A0 for revenue flights. As flight nears, even if no new booking is made, any of the following could happen: it could remain the same till the end (F2 A0), or become F2 A1 or F2 A2, or even - still without any new F booking whatsoever, if for instance J is overbooked, become F0 A0. The bucket for redemption is Z and right now you seem to be Z0 too. To be honest, with F2, unless some people cancel or there is an equipment change, I have serious doubt that any Z availability will appear in your case.