Yes. Had "High School" in the school name, so did all the others in the area. Could be a regional thing but I know people hundreds of miles away that also went to "High Schools". My school was founded in 1760, originally a "Free school", then "Secondary/ grammar school" in 1872 then a "High School" in 1900.
Seems I'm far from not being the only one, so not exceptionally rare at all.
https://www.reddit.com/r/AskUK/comments/glcvc9/is_it_common_for_british_people_to_call_secondary/
One comment: "The term "high school" has been in English for over five hundred years, so it's definitely not a US thing. "Secondary school" is only about two hundred years old, and didn't become the norm until the early 1900s.
"High school" has continued to be used regionally in England. Increased use of the term overall is simply a reversion to the previous word and not a US influence."