Hi Shirley
A number of people in the HASANZ Register could potentially help. https://register.hasanz.org.nz/search/ You can use the advance search functionality.
Alternatively some of the compliance certifiers provide advice. https://compliancecertifiers.worksafe.govt.nz/
Thanks
Philip

HSNOCOP 42 Storage of Class 3.1 substances in retail stores conforming to AS/NZS 3833
Approved: May 2010

The purpose of the code is to overcome the restriction of 2350 litres of flammable liquids that can be kept in a retail store without the need to comply with specified separation distances. Retailers have found it impossible to keep stocks below this figure in the new large format retail stores and typical stock levels can be up to about 10,000 litres.

This code can be purchased from New Zealand Retailers Association Incorporated: www.retail.org.nz

You can also view a hard copy of the Code at our office in Wellington.

https://www.epa.govt.nz/industry-areas/hazardous-substances/rules-for-hazardous-substances/codes-of-practice-for-hazardous-substances/

Our approach was to get the supplier of the aerosols to advise and provide solutions and it worked really well. They came to site looked at the problem then provided lockable cabinets, and assisting with separation of product

Just to throw another spanner in these works: What do the building's and company's insurers have to say on the matter? With fire protection, it is often these requirements that are a driving factor.