Irish /o/

I was talking to a girl from Dublin just a few days ago. I expected monophtongal /o/ and /e/ and, indeed, that's what she had for the most part. However, she pronounced "no" [n@U] in a very RP-like manner. In the same context, her "so" was clearly a monophtong [so:]. Has anyone else noticed this before? Is this a peculiarity of this speaker.

I've never heard an alternation like that, but I've read that Dublin speakers use [eI] and [@U] diphthongs for FACE and GOAT vowels. There is some alternation between closed and open syllables though, making 'days' distinct from 'daze' though I can't remember which one has the diphtong. The other realisation of FACE is with [E:].