In my opinion, it can't be overstated how important it is that episodes like this exist. Yes, Doctor Who has "done racism" before, but only in a superficial sense. Much toil went into making South Africa look and sound like Montgomery, and the result is seamless. Multiple scenes bring the best out of this odd bunch of companions—while there were inevitably complaints about politically correct casting, this episode simply would not have worked without the angle Yaz and Ryan can provide. All these are successes, but my personal favourite is Graham's "he's my grandson", not out of pride, but just in a matter-of-fact way that simply does not compute in this time and place. Too political my backside: Sydney Newman himself believed that the greatest thing about science fiction was that it was an interesting and safe way of talking about problems in the real world. As such, Rosa couldn't be much closer to the show's original vision. It's not perfect. But almost every time I revisit these episodes they're better than the last time I saw them. I hope other people will have the same thoughts over time.