I know that /ɑː/ is open back unrounded vowel and is found a lot in British English. It is the vowel in bath, father, bar, car etc in British English. In American English, this vowel is found in bar, father, car (but not bath!).
I listened to many British people when pronouncing this vowel and they do not sound like this at all to me (non-native). If I heard them correctly, they were pronouncing /ɑː/ as not [ɑː] but something more relaxed or at least not that back and long as the audios in the above websites suggest.
Question: Do British people usually pronounce /ɑː/ as [ɑː] or relaxed and shorter than [ɑː]? Am I hearing them correctly?