Using 24/48/144 hour visa NZ- Shanghai - London

Hi there.

I am flying Auckland via SH to London Heathrow and having just over 24 hours in SH on the way back.
I was intending on using one the transit visa options so I can go into SH but can I still do this now everyone has to get fingerprinted and will I have to go to the consulate in the UK or can this be done on arrival in SH in conjunction with transit visa?

Is the consulate appointment only for when a full visa is required?