This article doesn't list its source. Until I hear it directly from Asus, I'd take it lightly.
It probably is for the UK ot Europe in general but even if I saw it posted on the Asus web site I wouldn't trust it. The last official word I heard from Asus was that the Prime would ship this week - they denied that there were any delays. We had to wait until we saw that no 64Gb units were shipping to find out it had been delayed and that Asus had only told half truths. The only time you will know for sure is when it starts shipping.