If I need my China work visa on Friday 1st July, when is the last day I can go to make the application?

I'm leaving Japan on Sunday 3rd July to go home to the UK for a holiday, but before I leave, I am hoping to get my work visa for my new job in China. I am waiting for my new employer to send me the documents which should arrive today, tomorrow or Thursday. If I pay the extra 3000Yen what is the last day I can go to the embassy to start the process? Thanks.