When Harry registered the Travelix (?) webpage, he did not use his HRH but, as agreed, only his title. Which seems to be "Prince Henry Charles Albert David, duke of Sussex". That's correct, he is a prince of the Uk and Duke of Sussex.
What interests me is: how is the correct title of Meghan without the HRH? She, as his wife, shares his titles. So is she now "Princess Henry Charles Albert David, duchess of Sussex"? Or "Princess Henry, Rachel Meghan, duchess of Sussex"? Or just "Princess Henry, duchess of Sussex?" Or just Meghan, duchess of Sussex without the princely title?