the strange English that a native from Bristol would never, ever use but which a Pole stylistically would
Indeed - some random bits -
last year I participated in an intensive Polish course
Brits at least would always say "took part" and not "participated".
Cracow is more or less obsolete in British English - Krakow is the accepted modern spelling.
about the course of lessons
Beautiful Polish mistake there - using "course" in this context, as a direct translation of "kurs" is a telltale sign.
Was/is it just a boring word drilling
No Brit would ever make this kind of mistake.
I wonder, if your classes looked alike?
We'd also say "looked the same" rather than "looked alike".