Dreamtime is the first trip in the Tardis for the Seventh Doctor's new companion Hex: some splendid audio-scapes conveying the double weirdness of the landscape - Uluru is bizarre enough in the first place, but to find it on an atmospheric asteroid is extra value. I'm not sure if the plot really made a lot of sense but I enjoyed the ride.
In Catch-1782, the Sixth Doctor takes Mel to visit her scientist uncle, and then has to rescue her from a timewarp in which she risks being married off to one of her own ancestors. The plot is not very original, but Bonnie Langford is terrific as Mel in this - clearly Big Finish allowed her to find depths in the character that were impossible on TV.
In summary, three unexceptional but decent plays.