@kcorey If I’m understanding correctly, you’re asking how you could test the Geo-IP redirection of an ES Country redirect… by making the request from a GB based IP address?
I could be wrong, but I strongly suspect that isn’t possible.
I’ve never seen any override flags/functionality or additional parameters for adjusting/manipulating the behaviour of the Country condition of a redirect.
The only way I know of to test it is to use a VPN to adjust your IP address to the desired target location and then accessing the site.
If the rules were language based you could adjust the Accept-Language as you have in your example request, but obviously the language someone has set in their browser isn’t a great indication of their location on the planet.
If I could, perhaps, set a cookie expressly for testing saying “ignore my IP geolocation, override it to pretend I’m in another country for this test”, then it would be a doddle to create automated tests for all my locales that run on a single machine very quickly.
If we have to bring a VPN into it, we get added complexity and cost to testing.