On Writing Well and Elements of Style were required reading in almost every English class I took. Sounds like you had some bad teachers.

It's not a part of our curriculum in the UK. I, and many others like me, had never heard of him before.

Completely agree. However I first read the Elements of Style. In 2 days of reading Strunk & White I unlearned 3 years of high school English. Later I read Zinsser and found him to be saying the same things. But a lot of people say that Zinsser's take is easier to read.