If you're looking for period correct, very easy to get in and out of seats, look for Recaro's from the '70's. There are tons of them around, because they were OEM in some BMW's, and you can still buy the knobs and trim pieces from Recaro. They are a bit smaller, thinner and lighter than the Corvette seats too. If you're looking for period correct racing or rally style seats, try GTS Classics ( https://www.classiccarseats.com/ ). I can assure you they'll have no problem shipping seats to New Zealand!
PANTERA INTERNATIONAL
A DE TOMASO CAR CLUB
Presents the De Tomaso Forums
The On-Line Meeting Place for De Tomaso Owners and Enthusiasts From Around the World
Clicking on the banner will take you to the sponsor's website.