After telling you that you don't sound Australian, every British person you meet will attempt to mimic your accent. It's a weird English impulse, like apologising for the weather or offering you tea or denying the violent realities of their colonial past. They can't help themselves. The thing is, despite being exposed to a decent amount of Australian pop culture and despite having you right there in front of them speaking in an Australian accent, whatever they try will sound pure New Zealander.