[Guzzman]

I've just looked up a bit more information from my records that backs up the idea that your button might be from New Zealand.

The first Naval Volunteer units in New Zealand were formed in 1858 in Auckland and Nelson.

Over the rest of the 19th century Naval Volunteer units were formed in various ports such as Bluff, Wanganui and Wairoa.

The Naval Volunteer units were reorganised into Naval Artillery Volunteers in 1883.

The fact that your button simply states 'NV' as opposed to 'NAV' suggests that this is a button from the period 1858 - 83, prior to the reorganisation.

Most other naval volunteer units around the Empire tended to incorporate the name of the colony - NSW (New South Wales) or N (Natal) - into their title but this was never the case in New Zealand. Most units there were named for their location, i.e. Wanganui Naval Volunteers, so a non-specific button that could be worn by all units was the norm.

Pete