去英國讀大學需唔需要考gce?

You can apply to UK university with HKAL via UCAS. It may be true that GCE is easier than HKAL. However, for oxbridge, only only the result (AAA), you also need to proof why you are better than others during the interview as it is not difficult to get AAA these days.

When you apply for University in UK, the university are aware that HKAL is harder.

If you have spare time, it would be more benefitical to take GCE as well. However, you should also focus to get the best grade in HKAL first.

Good luck.