Doctor Who: The Kingmaker

Yes, this is a comedy, and, while it's not really a straight historical, it doesn't have any proper monsters in it, either, so it might not be what everyone wants from Doctor Who. But it is funny, and has quite a good plot, told from a number of different perspectives. It's a good change of pace, and makes use of the fact that Davison is a skilled comic actor, to deliver something that's basically an enormous amount of fun. And a completely bonkers explanation of what, exactly, happened to the Princes in the Tower.