The news coverage months ago (I might have linked to it in The Grauniad or Telegraph) said Charlotte Green (56) and Harriet Cass (60) had chosen to go.
There's an across the board requirement in the BBC for departments to downsize (odd, if they downsized 'talent' fees by 10% it would save much more than the cost of a couple of well liked staff like Charlotte and Harriet, I'm sure!).
My guess is that they if they want to (and Harriet might just decide to be a lady of leisure) they will be able to get voiceover work, and with Charlotte having very clear RP, her voice will be in much demand, whether she likes it or not!