/ɔː/ rather than /ɒ/

[thatone]

Most British people I hear on TV, radio etc. have [ɔ̞] instead of /ɒ/ and [o̟ː] or [o̟ʊ] for /ɔ:/.

The final /i/ to /e/ phenomenon is very common in singing, regardless of accent.

[5jj]

Most British people I hear on TV, radio etc. have [ɔ̞] instead of /ɒ/ and [o̟ː] or [o̟ʊ] for /ɔ:/.

You can't really say that they have X (= phonetic transcription) rather than Y (= phonemic transcription). One of the points of a phonemic transcription is that it can represent a whole range of phonetic transcriptions. It is not normally a good idea to mix the two, unless one is establishing what one means by a phonemic transcription - for example, "The quality [of RP /ɒ/] is that of an open lip rounded C[ɑ]..."*

* Cruttenden, Alan (2001) Gimson's Pronunciation of English (6th edn), London: Arnold.