We had British English in year 5-7 and 9, US English in year 8 and 10, whatever we wanted in 11-13 and I spent a year in the US between 11 and 12.
My English language pronunciation/accent is a mess.
I recently tried to work on unifying it towards US English. After all I use US spelling, too.
But maybe with the US going down and becoming unvisitable maybe I should have chosen British English.