Was/is your Roku user account based in the US when it was created? That would cause this. I believe that @RokuDanny-R might be able to assist you. But you might need to create a UK Roku user account and reset your Roku.
Dan Ultra (4640), Ultra (4670), Ultra (4800), Premiere (3920), Insignia 720p Roku TV, Sharp 4K Roku TV, Nvidia Shield, Windows 10 Pro x64 running Serviio and Plex on a wired Gigabit network.