Zons shipping allowing checkout when not available

Hello

I am using MZMT and the zones shipping module to split the World up.
Shipping has different pricing under 1 kg and over 1 kg

Through playing with the modules it was apparent that I could not have duplicate Countries in the same module even if the pricing was different so I had to use both.

MZMT handles weights over 1kg and Zones handles everything under
However when the weight of an order is in excess of 1kg the zones module is still showing with a message that the shipping fee cannot be calculated at this time.

That would be fine as MZMT has the correct rate but the Zones shipping module has a radio button and to my annoyance lets you proceed to checkout without paying a shipping fee.

I need to find a way to stop this happening and need some suggestions.
Hiding the radio button on the zones shipping method when the shipping cost is 0 would be my preferred choice.

Thanks