Despite contacting a number of retailers whose details I got from the Kingspan "our suppliers" webpage, and speaking to one of their sales reps, I was unable to get my hands on any of these Kingspan loft boards. Eventually I went with Xtratherm instead.
Not a cheap form of insulation, that's for sure. I covered about half of my attic with these boards, costing €900. The other half I'm going to cover with rolled insulation. This is coming in at €180. So, the loft board insulation costs about five times as much. The advantage is that you do get to use (some of) the attic as storage space. Handy for the likes of Christmas decorations, suitcases and other items that get used only once a year or so.
Interestingly, the pallets that the boards were delivered on are made from the same rigid insulation as is used for the boards. I suspect the insulation must be a very cheap product to manufacture if it costs less to used it to make pallets rather the timber!