This will depend on your nationality and if not UK/Irish citizen what type of visa you are entering on, as this dictates what health care protocol you would be eligible for during a 6 month visit. Pragmatically bring as much supplies as you can get - just keep insulin in the fridge once here. Plus copies of all tests done for HK diagnosis, HK doctor's letter re your current prescription, etc. In your shoes I would ask for c-peptide and all insulin antibodies testing while still in HK - these results will help clear up whether T1 or T2 - care pathways are very different for each type under the NHS system.