The 'nobs' of Cowdray Park - the home of British polo - refer to a polo field. A 'maidan' was certainly the name for such a field in the days of the Indian Raj, since 'maidan' - from Persian/Urdu - referred to a large open space such as a parade-ground or sports arena. Perhaps there are those who still use the word.
I don't know the source of either of your other queries, I'm afraid.



