County Meath 2
Image by ryaner

I'm also wondering if they are anything to do with the now abandoned plans for Killen Castle hotel and golf resort, which was to be in the area? I think construction began in 2005 and they were to put in stocked lakes for fishing etc. Will see if I can find out more on this.

Should be 'Killeen Castle'...

See here as well: http://www.wordwellbooks.com/book.php?id=528 sounds like they had plans for a heritage walk in the Killeen Castle golf resort, could well be it as it's roughly in the right geographic area.