JustKaty: Yep, it's definitely gone :-(
Seems somehow poetic that the 'something missing' has now been installed, and the cache itself is now missing!
The bridge was installed by Hamilton City Council in August 2016, and was opened with a community celebration, organised by the North East Community Hub, on 21 August 2016. With the bridge installed, and the walkway round the lake now complete, this area is much more widely used and perhaps not such a suitable spot for a geocache.
Will archive this one and the space is now free for any other cache owners who might like to place one near here...