Man-Eater at Surrey Green

No argument here....but at least the supporting characters were alright.

"Hot sun, cool breeze, white horse on the sea, and a big shot of vitamin B in me!"

On the contrary -- one of the most delightfully daft & engaging episodes, so thoroughly English in dry wit & humor.

Also a few steps into Quatermass territory, which is extra fun.

Incredibly, this remains the only episode without a central villain; in fact, the entire cast, apart from Sir Lyle, winds up becoming plant food, in an eerie touch. The empty pub clearly shows just how deadly the menace is, hardly a contender for worst episode.

"I take pleasure in great beauty" - James Bond

I agree with the OP.

To me, there's a difference between artful tongue-in-cheek dialogue and whimsical situations, and mere half-baked silliness.

As a US viewer and "Addams Family" fan, it didn't help that the extraterrestrial plant/monster was quite similar to Morticia Addams' man-eating "African strangler", Cleopatra.

Diana Rigg in her slinky leatherware notwithstanding, the denouement was so clumsy and silly that it squandered the interesting twist: a plant-zombified Rigg and Steed going mano-a-mano.

The would-be climax was also botched by the intelligence-insulting plot point involving the use of a "herbicide" in a small (2-liter) bottle or jug to overcome the house-sized plant.

It was simply preposterous to watch this bottle being repeatedly kicked over during the climactic donnybrook, spilling a considerable amount of its contents each time. Yet enough remained to conveniently kill off this vast and thriving plant with a mere splash upon one bit of it.

Even if they were going for an obviously surrealistic, light tone they didn't put enough thought or care into the closing scenes.