Hi wilful! It's a good review you've written about your NHC CVT, pointing out some real pros and cons! The bumpy ride you face could be because of hard compound or over-inflated tyres. The FE which you quote sounds really good to me according to the description of the roads by you. Over all, its a auto tranny! The NHC has a soft suspension I think. On the other hand, loud thuds are better than 'thunk's which the cars with stiff suspension face.
Post some pictures of your car please..
Take a picture of the auto tranny gearshift.
cya
A