No the chemistry answer is just wrong. Just because you have sex with someone doesn't mean you have actual chemistry. All kinds of people have sex. Anyone can do it - it's easy, especially if your conventionally attractive tv detectives. What Steed and Mrs. Peel had was irreplaceable. That category should be retired, with just a photo of those two looking at each other, in its place.
That changes the total in Mrs. Peel's favor, as it should.