i am currently in uk arm forces and thinking to visit my relative in hong kong

If you are now in UK, you can try to submit your application to Chinese embassy or consulates in your place. For HK requirements, you need to provide an Application Form, one passport-size photo; Valid passport with blank pages and a photocopy of the data page; Hong Kong guarantor (or company name)'s address, telephone number (if none, please fill in form with "No guarantor"). Copy of UK visa/Resident Permit (if any). Besides, Round trip air-ticket booking list, hotel reservation, bank statement and employed certificate may also be required.