Entering on a one way flight, but having a flight to Hong Kong

Hi, my husband and i are British passport holders and will be applying for our Chinese visa in London. We have a whole Itinerary planned with some hotels booked as we would like to get a 60day visa (HOPEFULLY). We will be entering china on a one way flight as we have a flight booked from hong kong to japan just before our visa in theory runs out. My Question is this enough proof we will be leaving the country to get our visa permitted or do i need a flight booked directly out of china to get our visas.