Trustworthy pre-owned dealers in China

[Polokus]

Hi, I’m new here and it’s a pleasure to meet you all!

Since it’s my first post, here comes a quick introduction. I’m French and I’m a long time watch enthusiastic, but haven’t had the chance to own any fine watch so far as I’ve been a student until last year and preferring to invest my money in other sorts of things (travels... ) rather than luxury timepieces. However this time is now over, and as I have now entered a more suitable financial situation, I’m intending to turn my haute horlogerie dreams into reality by purchasing the very first piece of my watch collection! And I quite naturally opted for a Rolex, and more specifically for a Submariner, model I’m totally in love with

Now here is my question for you guys. I’m currently expatriated in China for work, and I live partly in Hong Kong and partly in Mainland China (Jiangsu and Shanghai) depending on what my business requires.
I already visited quite a few AD stores in the cities I live in, but as you would expect, it’s absolutely impossible to find any stainless steel sport model, and worse than this, most of them didn’t even agree to consider adding me to a waitlist. So I’m going to start looking at the preowned market, and I would like to know if some of you knew any trustworthy dealers here in Jiangsu, Shanghai or HK.

Thanks a lot in advance for your feedback!