A place to start would be a UK AME that is authorised to carry out the HKG CAD medical and who should know exactly where to look. Just an email asking the CAD which AMEs in UK are approved by them shouldn't sound any alarms. This is what the CAA has to say about it, "
- Chronic hepatitis B – Certification may be considered in pilots in the ‘immune tolerant’ or ‘inactive HBV carrier state’.