MLBW, actually I don't trust many so called 'organic' producers, wherever they may be. If I lived close by to one as you did/do and I could see wth my own eyes that things were grown organically, picked at the peak etc I'd be more inclined to believe the hype. As it is even in Australia there have been lots of scandals about so called organic fruit and veg suppliers selling regular produce but heaping a bit of soil on everything to make it look organic!
This notwithstanding, I still don't see a big difference between the mainland and HK. If you compare HK to a place like Australia, a country without pollution, with clean water etc even regularly produced vegies in Oz would be healthier than 'organic' produce from HK. HK producers might not be as 'ethically challenged' as some Mainland producers but you can't get away from the fact that the environment here is one of the unhealthiest and it's in these conditions that fruit and veg are grown.
That said, I do miss good carrots so maybe I'll try out your contact