We are given an image of a postoffice.
We can see a sign reading Post Office Stanley. Searching for this in google and selexting images, we find similar images of the post office.
Clicking on one of the images we find the name of the post office.
It's called Post Office Stanley Falkland Islands. We can find it on Google Maps.
This gives us the flag.
byuctf{845P+98W, Ross Rd, Stanley FIQQ 1ZZ, Falkland Islands (Islas Malvinas)}