However, I am not happy that for the third consecutive story (after An Earthly Child and Relative Dimensions) a mistake made by Susan puts the world / the Doctor / everything at risk. I don't recall this plot line ever being used for the classic series; it's a bit unfortunate to do it even once, but three times in a row? Bring back the Susan whose grandfather was Geoffrey Bayldon, and who became President of Gallifrey. Also Tara-Louise Kaye is a bit uncertain as the guest cast, but we are told in the extras track that she was unwell on the day of recording. (Also that she is Carole Ann Ford's daughter.) And I thought it odd that a story set before the recent Eighth Doctor audio Relative Dimensions should be released after it.
So, rather oddly, an audio that I would recommend more strongly to listeners with no knowledge of Who than to those more familiar with the relevant continuity.