My review of the the Big Finish Companion Chronicles adventure 4.03 The Prisoner of Peladon staring David Troughton (son of the 2nd doctor) as King Peladon interacting with the 3rd Doctor is available at Amazon.com here.
This is a real departure from the Companion Chronicles series in that the King was a one-shot character rather than a regular companion, but it turns out to be pretty good. This is the 2nd Big Finish adventure that takes place on Peladon the first being 5th Doctor adventure the Bride of Peladon (Big finish 104). Ironically Nicola Bryant who plays Peri in that episode directs this one. It is a great start for her, of course it helps to have a solid Vets like Troughton and Briggs in the pot.
I don’t know if we will see more of Peladon but it’s a worthwhile start.