I managed to solve this by:
1) Removing the following line from bower.json:
"ngStorage": "0.3.0"
2) Installing momentjs using:
bower install -S momentjs
3) Reinstalling ngstorage using:
bower install -S ngstorage
I suspect the issue was that I had manually edited bower.json (hadn't used -S while installing) and had the wrong entry for the ngstorage dependency (it was nsStorage, but should have been ngstorage - case sensitive)