Hi. I've just found that the United Kingdom responds to the two-letter code "UK" not "GB".
I inserted the country name with the [CBC_COUNTRY /] code and it said, "United Kingdom" but I had "GB" as the country and the content didn't appear. When I changed the country code to "UK" the content appeared.
GB is listed on the ISO 3166 Country Codes list, but this plugin uses "UK".
I just took a guess at "UK" and it worked. But to help with trouble shooting, it could be useful to have a shortcode like [CBC_COUNTRY_SHORT /] that would display the two-letter code. That would mean we could easily find the correct shortcodes if any others don't follow the ISO 3166 list.