Missing diphthongs

The twentieth century RP featured four centring diphthongs, /ɪə/, /eə/, /ɔə/ and /ʊə/. But the speakers have dropped /ɔə/ completely and increasingly replacing the others with long monophthongs, [ɪː], [ɛː], [ɵː], [oː]. A Flyer download…⤵️ https://disk.yandex.ru/i/MTzHqAfPew9agA