Big Finish will be issuing an audio drama version of what was reportedly once planned to be the second ever Doctor Who story, The Masters of Luxor. And it has been read by Carole Ann Ford and William Russell.
EDIT: Unfortunately as an anonymous
reply to my post here kindly points out, it wasn't set in ancient Egypt! See the reply for what it may be about (and so may involve spoilers to the story). But it does include Susan.
Quote from Big Finish: "The season rounds off with the oft-requested
The Masters of Luxor, originally planned to be the second ever Doctor Who story (performed by William Russell and Carole Ann Ford). [...] All these titles are available to pre-order individually, or you can take out
CD or download subscriptions."