I am travelling for 5 months, where would be best place to apply for a Chinese tourist visa en route

I am a UK Passport holder. I leave the Uk on Dec 13 2012, and will only enter China via Shanghai on April 18 2013.
I will be travelling through South Africa, Brazil, Australia, and then ovelrand in Indonesia/ Singapore/Hong kong and Japan. Unfortunately the period in HK looks like it will be over a weekend