Independence Day, by Peter Darvill-Evans

Second paragraph of third chapter:

He kept his head lowered at first, and saw little apart from the soldiers' boots. Under the dust and dried mud they still shone like polished jet. He could see the muzzles of the soldiers' long guns.

A story about the Doctor and Ace visiting twin planets and freeing the population of one of them enslaved by the other. All fairly standard, though there is some gruesome offstage violence, torture and sexual assault. Ace gets to have a little fun but both she and the Doctor are thinly drawn. I see other reviewers on the net complaining that this was a disaster; not really fair, it's just a little below average.

Coming to the end of the Seventh Doctor spinoff literature: next and penultimate is the Telos novella Companion Piece, by Robert Perry and Mike Tucker.