I'm also in HK, and I went to the one cooper suggested, the impression looked a lot like the one Cooper has from siemens, everything seemed very professional. Then I went over to Thinking Group, which is the real dealer of Westones in HK and gave them my impressions and ordered. Please be aware their office for ordering customs are at Kwai Chung and not Wan Chai, I made that mistake today.... costed me a lot of time. Es5 plus artwork was $8,799hkd. The other shops that sell it (sometimes slightly cheaper) just send it to Thinking Group in the end, so if you don't mind waiting a few days for them to send it to and fro, then you could go to Mingoes or Hang Yuen. I prefer to do it with the dealer themselves to speed up the process.
Also, I think don't get mixed up, in HK the audiologist is not the dealer, two different things. The impression sure as heck matters, the recommended audiologist by Mingoes is the''failed' ones (it looks simplistic compared to the one I got as well) that Cooper showed (by Joyce Au?). Incidentally, many head-fiers in hong kong claim the isolation on their customs are poor compared to universals.... I wonder why....