This is a batty-little-old-lady episode. Whether you like it or not depends on how you feel about batty-little-old-lady scripts. I like them when I’m in the mood for them; other times they make me crazy.
Oh, sure, I realize the actual batty little old lady isn’t really in it much, but her spirit pervades most of the episode and its cornball sense of humor.
If you like that sense of humor, then you can skip the first fifteen minutes of this episode, because it’s just setup to get the handprint on the car. All you miss is some chase scenes and a little exposition.
If you don’t like that sense of humor, then you might as well skip this one entirely, because apart from the goofy bits there is very little to see here.
[As a side note, I shall now introduce the Avengers Chekhov’s Gun Variant (tm): If you have several unimpeachable high-level figures in a room (besides our heroes) when someone says “No one knows who the Fox is,” then one of those people is the Fox. Even Steed admits it. In this case, there are only two such people in the room, so your odds are fifty-fifty. To their credit, they don’t try to hide the Fox’s identity from the viewer for very long at all, which actually makes it more fun.]
There are two bits in this I very much enjoy, although I grant that it’s definitely Dukes of Hazzard school of humor. (If I’m being honest, there are times when I like that sort of thing, but do bear in mind that you never truly escape being from the South.) The first is when Steed completely baffles his partners with the radiator repair, and the second is when Purdey handles both the moonshine and the fighting better than Gambit does, and Gambit gets completely bent out of shape about it.
The “calling all cars” joke is pretty good, but the one in Johnny Dangerously (speaking of cornball) is probably still the all-time champion.
Like you say, you really have to be in the right mood to watch this one. I like it, it’s quirky, funny, and eccentric. I especially like the scene where Steed “fills out the holes”, with fresh eggs, incidentally an actual old trick that works very well. But the “music” lets it down, wayyyy down, for me. It makes it laughable to watch, and over the top. Yes it’s fun, but the music makes it seem more daft than it really should be. It’s just such a shame this is the last ever episode. Poor Steed!!
I am never in the right mood to watch this one, and I have tried on several occasions. To me it’s just stupid. The humor falls flat, the Canadian caricatures are actually kind of offensive, and the plot works so hard to get us to the extended “car chase” that it smacks of over-planning. It’s like a long, elaborate set-up for a very stupid, slightly racist pun.