What about trainers? In BrE that means sneakers. Canadiens usually say running shoes. Different countries, different words/grammar.

Hope that helps anyone who has gotten confused about the difference before - although if you said it, everyone would understand you, and 99.9% of people would not pick you up about it - although my Dad would!
I think you mean that 99.9% of the British people would understand you if you said "I was sat on the chair".