Re: An important lesson comes from this story
No, but appearing to be incompetent at being evil; and being caught and thought to be incompetent, will aid when you want to do actual evil competently elsewhere.
The thing to think of is: How to take the UK out of the international running right now? Make it look like Russia was involved in Brexit. Thin the herd of a few useless agents with a hope they may pop a known detractor off. They're expendable. It's a win-win scenario.
Using the knowledge that, frankly, the UK will muck up Brexit completely unaided, all they have to do is appear to be mucking around, get a few deadwood chaps caught to make it look like their not very good at this whole international spy thing, maybe off a detractor.
Honestly; it's a Xanathos Gambit!
(I'd apologise for people getting caught on a TV Tropes wiki hole, but frankly, they should know what they're doing, reading The Reg!)