> In the UK I think I'd have a hard time getting anything other than generic 'basmati'

It’s relatively easy to find any kind of rice in countries with significant East Asian diaspora like England provided you are ready to buy largish quantity (10kg). It’s highly likely there is an Asian market near you with a surprisingly large selection of rices (not necessarily on display) and which can get you other kinds if you order. It definitely is more involved than going to Tesco but far from impossible.