One of the aircraft there is the Piper PA25-235 Pawnee ZK-CEL c/n 25-2747.
Here are a few pics of it during its NZ career. Above shows her at Airwork in Christchurch in August of 1964.
Below it was captured at Hawera on 15-07-1984 with Farmers Aviation.
See the following links for many more details about the life of ZK-CEL.