Free UK postage but charging for overseas

Hi,
Can someone please help me as I am desperately trying to keep my free UK postage but want to charge just a simple flat rate to anyone abroad. At the moment under categories I have created an overseas postage token which on every listing states to purchase one unfortunately this has not worked & have got someone abroad purchased without the token. I have looked at setting up the zone rates but this seems to complicated seens as I only want to charge £2.50 flat for anyone purchasing outside the UK so any help will be appreciated - Thank you.

I don't know what an 'overseas postage token' is, but you need to set up at least one zone to do what you want to do:

https://www.zen-cart.com/tutorials/index.php?article=69

Hi,
Thanks will take a look. The overseas postage token is what I created myself within the categories section but unless people understand fully that they need to add that to basket also I am left with people overseas having free postage also.