Hello

I am an Australian passport holder travelling overland from Singapore to London by train. As part of the trip I will be taking the train from Hanoi to Beijing and then Beijing to Moscow with the Trans Siberian. I can apply for a Chinese visa in Australia but as it will take me more than 3 months to reach China the visa will expire. Is it possible to get a single entry Chinese visa for Australian passport holders in Vietnam? Many thanks for your help, Trish