Grosvneor Place is not single sex, just each 'flat' is single sex. so on your floor you will still have the opposite sex, just not in the adjacent rooms. there's plently of mixing going on dont worry.
EE08 means block E, floor E, room8. technically there arent any plats, just separate blocks and floors.
Grosvenor street building is definitely not ensuite, 2 showers per flat of 8. each flat is single sex but floors are mixed, same as grosvenor place.