Update :-
I never got around to doing this (yet)
What I will say though is that it only happened because in the tax system details I also had the
Also display (on the products list, product details and cart pages):
set to display "Rate Value and tax cost" , with that enabled it pushed the product options box off the side of the main screen , so the dropdown arrow box was not displayed.
By setting this to display 'nothing' I dont get the problem.
Lesson learned
