If freight cost is an issue, you can get from Custom Aquatics, they will send to NZ by much cheaper post than Marine Depot. Also they have SCWD in stock now, I already got one from them in my tank.
I dealt with both Custom Aquatics and Marine Depot, Marine Depot is excellent service, just they will only send by expensive freight. Custom Aquatics the service is sometimes a bit sloppy, but they generally have the best prices on the net. To deal with them they require you to send them a pic of both sides of your credit card if you're an overseas customer, opening the account was a hassle, but now it's open dealing with them is easy enough.