The Doctor Who Lost Stories - a range of full cast audiobooks made from adventures devised originally for TV but abandoned - are discussed on the fan website Kasterborous.
A new feature looks specifically at the most recent tales, starring Colin Baker (the Doctor on TV 1984-86) and his companion Peri (Nicola Bryant, 1984-86) and can be access at this link.
The stories covered include The Guardians of Prophecy (which featured the return of the Melkur from TV's The Keeper of Traken), Power Play (which sees the return of companion Victoria Waterfield, played by Deborah Watling, 1967-68) and The First Sontarans - an epic battle with the potato-headed clone warriors!
The Lost Stories are also available on subscription.
It's a new Who's Round, Toby Hadoke's Doctor Who 50th anniversary quest to get an anecdote about every single episode of Doctor Who to date. In this instalment, Toby looks back a full fifty years.