This is a fine episode. Benny is fun as she always is, and the idea of her meeting Sherlock Holmes sounds fun in theory. And I'm sure, if Victoriana and Sherlock are things that appeal to you, you would enjoy this episode a great deal, because it is absolutely full of Victorian atmosphere and tropes.

Unfortunately, I find that dull as ditchwater.

As I say, Benny is a highlight to me, as she always is. But this episode is long, chock full of weird 'period typical' sexism which for some reason modern writers always feel compelled to force into Victorian period fiction, and tediously boring as far as investigations go. I think, mostly, this one is just not for me. Even when it turns into aliens and SF-ness, it's still mostly just Benny and the aliens talking and talking and talking.

Benny wants her Time Ring back. And then she gets it. And it takes us an hour and fifteen minutes of tedium to get there.