OK. Managed to get the 'balanced column height' effect working (as described in Additional Information in the readme). For some reason the necessary outer div id when generated had an extra numeric attached (for example #navColumnMiddleWrapper2) which detached it from the id in the CSS.

Not sure why it's happening or how variable it may be, but either changing the #navColumnMiddleWrapper class in the CSS to suit, or (perhaps better) changing the class to an id (so make it .navColumnMiddleWrapper for CSS line 2) might at least be an interim fix.

Thanks again for letting me test.