Booked Return Flight Required? Or an exit flight to a different country ok?

Hi, I'm from the UK, looking to get a tourist l to China - I booked a one way flight (non-refundable), with the idea of booking an exit flight to one of the countries nearby (I just haven't decided where i'm going yet 0 either vietnam or malaysia probably). I'm looking to travel around Asia, so I will not be returning home. However, I'm now very worried that it is only a return flight they will accept to grant a entry permit. Does anyone know whether it must be a round trip (i.e return to the same country of origin within the same booking) OR whether a separate booking out of the country to a different country will be ok to gain the visa? I understand that exit flights are all immigration will look for when you land, but I'm worried the Embassy will not accept this for the visa?