"None of the listed pronunciations reflect the way the name is pronounced in Britain: "BEER-tris"."This is just a different interpretation of the first English pronunciation given ("BEE-ə-tris"). You obviously speak a non-rhotic variety of English (one that pronounces preconsonantal r's, if at all, as a neutral vowel ("ə")), as is generally regarded as standard in England. I doubt if anyone anywhere pronounces an actual r sound here. (Hope this is clear.)