You could find anyone in the country who speaks with an RP accent. In my experience, it comes from educated background, typically the south of England. But I've got some traces of regional accents not covered by RP. And there will be more podcasts in which I play you some real samples of British English in different accents. You can listen to them and get used to hearing different accents. Hopefully it will help you to start identifying different accents in English.