NZ New Zealand 1975 Waterfalls set of 24 colour separation proofs. Unique

Several of the values printed on these two sheets were never issued. There are two proofs of the 25c Papakorito which was only issued as a 16 cent value, 2 proofs of the 23c Marakopa which was only issued as the 14 cent value, and 2 proofs of the 18c Bridal Veil which was only issued as the 15 cent value.
Sent with Standard Delivery - Registered.