@DLosc What's interesting is that Wiktionary lists /wʌn/ as the IPA, which matches what I say (midwestern US), but the UK audio sample sounds to me like a slightly different vowel. Under
one, they give the Received Pronunciation as /wʌn/ but with a narrower transcription of [wɐn], which I guess means that RP renders the /ʌ/ phoneme as [ɐ], at least in some contexts.