From About the Author from the book Citadel of Dreams:

Dave Stone has written any number of things, from comics and radio scripts to full-length novels, which currently include Heart of TARDIS and The Slow Empire for the BBC Worldwide Doctor Who range and Professor Bernice Summerfield and the Infernal Nexus for Big Finish.  This is the first work published in the novella form, as opposed to a short story which didn't know when to stop, and he thought that with the relatively low word count it would be easy!

He thought that, but…