We didn't come back - we moved on to Singapore, which, unfortunately we are not liking as much at all!
Just some things to consider not about HK but any move abroad at your kids' ages - the 12-year-old only has a few years til GCSE, but then you look like you'll end up in a series of two-year cycles of exams with the 10 and 8-year-olds. You should consider how long you intend to stay or what are the natural break points for moving back or elsewhere.
A number of the schools in HK do iGCSE, so examination boards and curricula might be different to schools back in the UK; there are a lot that do IB as opposed to A levels, so again something to consider. Although it may seem a long time out, living anywhere abroad may impact your child's home fee status for Unis. It's not a very clear-cut rule but you should consider they may have to pay international fees - there's a thread somewhere on this topic, and you'll see that it can come as a shock to some folk.
And finally, I should flag that this last move from HK to SG for us has been with older teens, and it was significantly harder than with younger kids both in terms of their loss of friends but also making sure we kept them on a similar path curriculum/education-wise. So again, something to consider about any move abroad and when you'd come home.
Having said all that, HK has a lot of expats and overseas students, so whatever you decide, the schools are well set up to support you in making those choices and guiding you on the best options for the kids.