BOAC
I absolutely agree - ANY DOUBT - ASK.
But we have similar situations every day, they have to be clearly defined in international, not British or US regulations.
P.S.
from personal experience in ZBAA
ATC - niauoirjvnb....
P - say again, please
ATC - ffjvbriogiu...
P - say again?
ATC - rtoihyihjk...
P - confirm clear to land?
ATC - affirm!
P - thanks!