UK residents; How to apply for a Chinese visa if travelling by train from HK-Shenzhen-Guilin-Shangh?

A friend and I (who currently live in the UK, both with British passports) are planning on travelling in April 2013 from Hong Kong to Shen Zhen (on MTR) then getting a sleeper train through to Guilin, then up to ShangHai, then up to Beijing.

We should be in Shenzhen for a day only, and Gulin/Shanghai/Beijing for approx. 8 days, but we're struggling with what to do about applying for a Chinese visa. We're aware that we can get a Shenzhen voa at the border on arrival, but for the Chinese ones for the rest of the trip I believe we need confirmation of travel and of accomodation?

We were hoping to book the sleeper trains in Hong Kong (as I know you can't book them too far in advance), and the accomodation also. But if this is the case then can we not apply for a Chinese visa until we book everything else in HK?

We would really rather book in the UK before we go as we were hoping to not have to wait for it while away.

Can anyone advise?

Thanks!!! :)