UKCISA
She can delay university for three years while she works in UK (or anywhere in the EU) She'll probably get much more out of college that way as a plus.
Or, as she's been in HK for 7 years, she will count as a local student. HKU teaches in English, 42,000 HKD a year fees (vs 100,000 if overseas) Plus grants available, and cheaper as she can continue to live at home.
Are you or your wife still residents of UK? What I know some people do, is have the spouse & children continue to be declared resident in UK - but as they are actually spending much of the year in HK, and aren't working, there's no UK income tax to pay. But you have to do that at least 3 years prior.