i would set the chosen shipping country as a session variable, and use this variable in the shipping calculation.
(On your confirm page, you may already have this variable in place)
if (!session_id()) session_start();
if (isset($_POST["Checkout"]) || isset($_POST["Checkout_x"])) {
$_SESSION["eCartCheckoutForm_country"] = "".((isset($_POST["country"]))?$_POST["country"]:"") ."";
}
in your ecart object, under the shipping tab, you create 3 shipping rules, one for each of your possible shipping options.
eg for GB shipping, make the condition based on a session variable value, the variable name being what you call it, (it would be 'eCartCheckoutForm_country' using the above code) and the value = 'GB' and the calculation as a flat rate.
for europe shipping, make the condition based on a session variable value = 'AL' or 'AD' etc
eg