...[oʊ]...
Really? That sounds American to me (being American). I'd completely believe that it isn't fully [əʊ], but I'd be surprised if it is fully [oʊ] though.
Is the sampling based on:
1) Movies/television
2) Linguistics-affiliated academics (conferences, etc.)
extremely disproportionate to the statistics you're giving?
I may very well be wrong, but I feel like I'd be surprised in the UK, if I were to live there, if I almost always heard [oʊ].