I am very glad to say that I was not disappointed. The audio is about twice as long as the original series (four hour-long CDs), and Fisher has bulked out the material with lots more character background and atmosphere than was possible on screen - the full story of the campers gruesomely slain by the Ogri, for example, and various brazen but humorous infodumps. There are lots of decent sound effects as well. Very highly recommended.
I also went back and reread Terrance Dicks' original novelisation of the story for comparison. It must be a lot shorter than Fisher's new text. I noted of it three years ago that it is "a standard Dicks write-what's-on-the-screen treatment, somewhat flattening a rather good story" and I found no reason to change my views. I did think Dicks handled the climax of the story with some finesse, but the rest it pretty thin.
Posted via m.livejournal.com.