British National Working in China

I need to go to China for 4 months to project manage a Chinese fabrication company who my British company has contracted. During this period on the ground in China, I will continue to be paid in the UK by my UK firm, so i won't be getting paid in China and will continue to pay UK tax throughout these 4 months. Is it possible to get a multi entry M business visa to cover these 4 months or will i need a Z type? many thanks for your help.