Thank you all for the advices. But I really don't want to leave my baby & wife in the UK for one whole year....
agreed that we should really looked into this seriously before I accepted the job but when we looked into this last year most people told us that as long as she stay aboard for more than 12 months then she can apply for the dependent visa becuase I go there for work. but it turns out not the case
It would have been the case if you needed an Employment Visa or used a QMAS visa to enter HK. But because you are a HK Permanent Resident different rules apply.
if you don't want to leave your wife and baby in uk ( not sure about her uk residency though if she leave uk you need to ask uk imm.)
thousands of mainland born chinese spouses in HK obtain 2 way pass but she must renew this pass every 3 months for next 5 years at her hometown which is not the end of the world, this is very common in hk especially near border towns of tin shu wai, yuen long and sheung shui.
i also believe that spouses with a two way passes can not work during those 5 years(though a lot do illegal work as friends has a tutoring centre located in northern district and the cross border spouses who have students attend this centre told them this fact), either way, it's not going to be easy