They've 44 staff now, apparently and a pile of volunteers
IMO, there's something coming - having been a charity trustee when there was a problem, I know that one of the things you do is write to the Charity Commission saying "we found this issue, so were doing our statutory duty and informing you', and here are the measures we've taken to mitigate it". Showing that they take their responsibilities seriously is always a good look.
They may have had a head's up from the Charity Commission, or done an internal review, or had legal advice, or know there's more to come (e.g. in the press), but that's my reckon.
On the other hand, the lack of even an interim CEO name does make me wonder if Green flounced/has another issue. Maybe the trustees wanted to take an action she wouldn't countenance. Or maybe they just asked her to leave and didn't think ahead.