Just to be a bit serious, why the hell buy in Sunning? Their prices are badly over inflated and there is little to no negociation room. I think for the 85L (latest purchase), their price was 5000 RMB superior to what I paid in my favorite shop.
Check the taobao price average and head to your local computer city or photographer "mall" and negociate for that price. If you don't speak chinese, go with a friend (basic written numbers and hands communication can also work).
That way I'm almost always hit HK prices (and never had a lemon problem...or nikon bag issue )
Hey, usually I never buy in Sunning but I needed a fapiao (invoice). Their price was okay (12.790), including warranty and the fapiao. The lowest price I could find on taobao was around 11k, without warranty and fapiao or 11.9k with everything. So I paid less than 1k more which is okay. As for other lenses, yeah, they are heavily overpriced, but this one was almost similar to taobao. I was offered an imported Korean for 11.2 at my local shop, but without anything.
But you're right - I bought my 5D3 one month after it came out for 16k at my local "mall", while the price on taobao was around 19k. Now it's 16k, but back then I saved 4k.
I am waiting for an answer from CPL on my "request" ^^