I figured out why the rules were not working :)
I was using the value for eCartCheckoutForm_country as UK but it should have been GB.
I have the page working fine now, thanks for all your help.
However, my client has now asked for another option which I will require the customer selecting an option.
Currently, my shipping options are:
Standard UK Shipping - £3.75
Free shipping on orders over £75 inc vat
International Shipping £5.75
My client now would like a guaranteed next day shipping option with a value of £5.75. I am guessing that if the customer clicks a checkbox for next day shipping I will need to add £2 to the standard UK shipping charge. What would be the best way to impliment this and which page would this appear on, the cart page or confirm page?
Many thanks again
Kelly