Hi Frazer congratulations on taking your idea to the next level. I only know a peripheral amount about the apparel industry – have you thought about connecting with some one you respect who is further through their journey in their industry and might be able to share some insights or mentor you? Not sure if you have a network you could approach already or can stalk some one on linkedin or off their website?
Second, I would jump online and read every story I can find about starting out in clothing – there is lots of editorial and you might get some useful insights and tips that resonate with you.
Finally from a more business focused perspective there are lots of resources from ATEED, which is part of Auckland council (assuming you are in Auckland, other areas have different support but start with your local council…or google!). See this link for more info https://www.aucklandnz.com/business/start-and-grow/start
Hope this is helpful and feel free to post more details if you need more specific advice. Good luck! Vicky