This was the Doctor Who novel which was turned down by the BBC and which Mortimore subsequently managed to get published privately, now downloadable for free thanks to those awfully nice New Zealand chaps. There is no way the BBC could have published it - by Mortimore's own (rather too extensively documented) account, it is about a million light years away from the novel he actually agreed to write. But it is a brilliant read all the same, though I think you would need to know who Lola McGovern and Cliff were to really appreciate it. It is the story of the First Doctor, his grand-daughter and the two people from 1960s England who travel together, in the Tardis after an adventure with Alexander the Great and several ambiguous outcomes, trying to cope with the disappearance of the entire universe outside the Ship. Mortimore takes the narrative to very peculiar structures and places, but it kept me reading.
The New Zealand edition includes both Mortimore's authorial notes, describing his bitter struggles with his muse (incarnate as a monkey), and an account of his dispute with the BBC publishers which I think could usefully have been summarised into rather fewer pages.