Anyone know if there are still restrictions on only being able to use avios for flights originating in the country your exec club account is registered in.

I know a few years ago I got caught out on booking a flight for someone else that I assured them I could upgrade once they had booked it, only to find out after they had booked that there was a restriction that avios could only be used to upgrade flights that started in (and were therefore ticketed from) the home country of the exec club member. I want to book and upgrade for someone who lives in a different country to me and don't want to get caught out again, but I can't find anything on ba.com anymore about this so perhaps this restriction has been removed