I had previously been using iScroll plugin but wanted to drop it for the native behaviour.
The initial implementation was using
webkit-overflow-scrolling: auto;
however I updated this to ...
webkit-overflow-scrolling: touch
.. to enable the motion/inertia on the touch scroll.
The issue with this is the list items contained within the navigation disappear completely when scrolling, and only return once the momentum has come to a rest.
An example of this can be seen here