You can still exchange HK driving licences into GB licences. You just need to prove that you took your driving test in HK. I did this.

The same is true for exchanging licences from any country that DVLA accepts.

Another "loophole" was if you are over 25, you can exchange an HK licence to NSW (Australia) licence without a test, and then you could exchange the NSW licence to a GB licence. But now you have to prove that you took a test in NSW.

HK driving licence in HK requires an ID (which could be passport) as there is no photo, obviously.

When applying for GB licence, you need to submit your ID anyway.