Dumbarton Avenue is associated with the Hamilton family who owned the estate here in earlier times. Dumbarton recalls the name of a town and castle in Scotland from where the pioneer businessman Robert Hamilton came. The Scottish name is derived from Dun Breton - “the hill (fort) of the Britons”. Hamilton was one of the financiers of a private and unofficial hospital where sick and wounded British prisoners-of-war as well as Boer wounded were nursed during the Boer War (1899-1902). It was known as Bourke’s Hospital.
These days you may see the “Blue-light Brigade” passing as the street is next to the Presidential grounds, Bryntirion. So be vigilant of muggles as there may be a few pedestrians.
The owners of the property is aware of the cache and has given their consent. No need for climbing or entering to find the nano.
Source: the local "Arcadian", November 2013 - the newsletter of the Arcadian Residents and Ratepayers Association (ARRA)
Important note: cellphone reception is bad here and using it to navigate will typically show the coordinates on the Eastern side of the road. It is not. Stay OFF the vice-president's fence, it's on the Western side!