Chris,
Dont bother in trying to get an Oz early 911 with a/c that actually works.
For most of the few attempts to do this excercise from local shops (butchers) it is/was hard to tell if the system was even on or not(ask me how I know)
Factory RHD units were not readily available here until the mid '70s and were not all that sucessful due to the differences in the bulkhead and front pass side footwell to the US 911s.
The original 901 was not designed with a/c in mind in 1963,nor even with a good ventilation system.Look at the Toyotas of the that era !
Sorry to be a bit negative,but I am trying to give you some of the bad news before you part with your HK$$$.
In Sydney,we just roll the windows down even further !
Cheers,
Dennis.