“These guilty secrets are either mistakes that I have to take real care to avoid or perceived errors that I don’t see any wrong in.”

I have to admit that I never notice the misuse of less and fewer. I make this mistake all the time.

But if something becomes such common standard usage (like ‘their’ etc. for he/she), then doesn’t that mean it’s become normal English and you’re allowed to say/write it? Most people use less instead of fewer these days.

Also, I and about three hundred years of writing history support your use of the singular their. For Pete’s sake, even Jane Austen used it. How long does a thing have to be in common usage before it becomes common usage?

If you’re interested, collective nouns such as sports teams and governing bodies are referred to as a singular in French as well. And since you have genders for them, you effectively refer to a football team as “she” if it is the subject of a sentence, for example, whereas in English I would always say “they”. Perhaps it is an example of a grammar rule which has mutated in the UK, but remained in its original form since the settlers arrived in America?

Terry Wogan is a big fan of literally pulling people up (by their hair, usually) when it comes to being ’sat’ rather than sitting. Of course, it can sometimes be correct to say you were sat somewhere, e.g. on those occasions when you have genuinely been placed in position by someone else. But I rarely see this happen, except when I’m sat on buses home after midnight.