I see Severin are releasing the two Amicus Dalek films.
Both have commentaries with '
Whovians' Barry Forshaw, Stephen Jones and Kim Newman.
Whilst Invasion Earth 2150 also has an interview With
Doctor Who Expert Stephen Thrower. (First i've heard of that - thank heavens he doesn't write books on the subject. There's be six new Doctors by the time one was published)