Hi Paul,
Welcome to the club.
My understanding is that cars originally supplied to the Irish market did not mirror the model lineup available in the UK. The cars on sale here were spec'd by Lexus Ireland and sourced directly from Japan.
With regard to the Mark Levinson sound system, while it does sound terrific, I would agree that it can be problematic. I had an IS250 SE-L, 2006, with ML and the American made amp failed. Luckily I sourced a replacement from Ebay.
Best of luck with the new car.
Dec.