Due to a small miscommunication, we have ended up with a flush box inside a cabinet. This isn't a bad thing if you want to add a power point later, but one is not needed now and the installation of a standard blanking plate will limit choices for shelf locations as they are too thick.

Can anyone recommend a slim metal plate that will fit over NZ flush boxes (I.e. the size of a normal power point)?

RS Online sells some under their own brand, but they lack dimensions or hole spacing, so I'd prefer to buy something local that has been verified to work.