Only certain addons (1channel, icefilms) use web addresses which are blocked by UK ISPs. With those addons you will not even see lists of films let allow error messages when trying to play them. The error messages you are seeing are likely due to other causes (except on the above addons). You can circumvent isp blocking for the above addons by using proxy web addresses (look it up) although performance may be compromised, as well as using a vpn. You can view the films in the countries you select because they are not being isp blocked by uk isps.