We are NZ ers travelling back from London via Shanghai staying 76 hours do we need different visa

So you will have a return trip from/to London via Shanghai? If so, it is fine to apply for a regular transit visa, which is usually valid for 7 days. If you will take a route of "another international area - Shanghai - London", you are qualified for the 72h visa free policy and the 72h starts to be counted from the next 00:00 after your arrival. Therefore, probably you can still use the policy, no need to apply for any visa.