Someone wrote on Twitter that British Nationals Overseas applications might have been blocked from HK but then I remembered that you don't have the Shield, so it was strange. Can you try the BNO form and check if it works?
@clacke Ah right, so it's probably just the regular visa form https://www.gov.uk/check-uk-visa but you need to select Hong Kong (British nationals overseas) in the second step. But the if the first works, I see no reason it would work...
Thank you very much, in any case this confirms there is no blockade in place ! π