Is there anywhere in Wellington that sells DVS spares.

Looking for hopefully a cheap diffuser? (the roughly 30cm disc that screws into the ceiling vent).
Plan on fixing a WiFi access point into it but don't want to wreck the existing one (rental property).

I realise I could just contact DVS but suspect they are either pricey(+ postage) or could end up on a contact list for maintenance parts.
 

Thanks in advance