Chinese work permit and dual passports

I have a PRC work permit/ residence permit in my South African passport, I also have a British passport, I will be traveling to Europe and then back to CN, with my British passport I dont need a visa for Europe but can I leave and re-enter CN on my South African passport (reflecting my permit to be in CN) and enter and leave Europe on my British passport? Or will China not let me travel to Europe with out seeing a visa in my SA passport