Brit_HK_Teacher

Hello, I am a British Citizen, working in Hong Kong as a teacher. My salary earned in Hong Kong is taxed over there, and it is my understanding that HK and the UK have a tax agreement. I wish to transfer my savings to a cash ISA in the UK. I read that, even though I was born and raised in the UK I am technically classed as a UK non resident. My questions: 1) Am I permitted to still use the cash ISAs I created while I was in the UK and pay into them with savings earned in Hong Kong? 2) Could I create a new stocks and shares ISA in the UK and put my savings into that? 3) If the answer is no to the above, should I just keep my savings in an online savings account? 4) For the interest earned in this savings account have to be reported if it exceeds my personal allowance of GBP 5,000? If so how would I report that and when? Your advice would be much appreciated, as I do not wish to accidentally make a mistake and land myself in hot water! Thank you.