UK citizen getting a Chinese visa in Belgium

Hi,

I will be trying to get a F/M/X2 type however will only have 5 working day window to do so in the UK. Do you think this is realistic or should I try and get that in Hong Kong? Is it possible to get it in 24 hours in Hong Kong? I heard it is not possible to change from a tourist L type to any other kind, is this correct? Thanks