If I see the following words, I consider the writer to be British.
Labour instead of labor
Neighbour instead of neighbor
Urbanisation instead of urbanization
The ground floor
I don’t think it’s so important for the learners. English is existing now in different shapes: Brit. English, Am. English, Can. English, Austr. English - but they all are only various forms of a modern lively English.
The differences are interesting first of all for the philologists and some finical students.