for economics........4 out of G5 have it, and i guess warwick should count instead of IC in this field.
acadecmially, yes.
for working purpose (in HK), quite sure so for oxbridge, lse. ucl and warwick will not be too far different from hku, cuhk, ust except the oversea experience. If in UK (banking), G5+ warwick are target. a huge gap with those afterwards.
to OP:
study in HK then find job in HK = difficult, especially when you are not top enough for international company (i.e. solely english as office language), and you dont speak cantonese.
study in UK then find job in UK = super difficult, visa
study in UK then find job in HK = go back home sleep, especially when you are not in G5, and you are not there for interview (location problem). this is not a problem for people from HK (many locals go study in US/UK) as they can stay forever and have time to find job.