I'm not in NZ and I'm not experienced in sausage making, but just looking at the available (and woefully incomplete) specs and prices of the three, I'd go for the one in the quote above. It has plenty of power, seems to be constructed of high quality materials, and fits within your budget. It also comes with two plates. It doesn't say if it's a #12 or #22, but it looks like a #12, just judging by the pictures. A #12 is perfect for much more than your anticipated use, in my opinion. A #22 is beyond overkill in terms of capacity, weight, and expense.
On the con side, that one from Save Barn is heavy. If you are going to have to move it every time you use it, make sure you're comfortable with lifting 28 kg up to table or counter height. That's about the size and weight of my #12 grinder too. I have to store mine out of the way and then bring it out to the counter whenever I want to use it. I find it heavy, but manageable.
One of your other choices, the N12 from Foodquip, comes with only one plate, a 6mm or an 8mm depending on the model. And also depending on the model, it has plastic parts. I'm more or less against plastic when it comes to heavy equipment like this.
The T-22 Tre Spade on the Netropolitan site is likely a good grinder, perhaps the best quality of the three, but very little is provided in the way of specs, so it's hard to know for sure. However, it's well over your budget, and it's a #22. I'd rule it out based on either of those factors if it were on my list.
Remember that no matter which one you buy, you are likely going to want to buy more plates. The Save Barn grinder comes with a 6mm and an 8mm. You'll probably want to add a 4mm and a 10mm to augment those.
I'm not expert. These are just my opinions.