Anybody know the exact difference in spec between Irish Octy Vrs FL and the UK spec?

No definitive list, but I've seen pics of Irish FL vRSes on here with the older style 17" Zenith alloys, whereas all UK FLs come with Neptunes.

Edit: also more info here: http://briskoda.net/forums/topic/203989-vrs-specs-uk-vs-ireland/

Are the Neptunes 18"?

Are the Neptunes 18"?

Yes.

(Zeniths are also available in 18" too, but from what I've read it's the 17" version as standard in Ireland)

Another review of a 2010 Irish vRS here: http://briskoda.net/forums/topic/152092-irish-times-review-vrs-10022010/page__view__findpost__p__1891221

Specs at the bottom of the post.