Have you tried Equipet? They sell a lot of horse-related products, but I don't know if they sell those mats. They have branches in Navan, Ashbourne and Drogheda, but the only one listed in the Golden Pages is the Ashbourne branch, if you want to give them a ring. The number is: (01)8352702.
Oh, and a quick search on Google found this site: [broken link removed]
I saw an ad recently in the Irish Field from TRI at the Curragh [broken link removed] advertising rubber matting for sale. Can't find anything on their website so maybe give them a call.
http://www.kraiburg.co.uk/ (Country Life in Donaghmore) http://www.matman.uk.com/ http://www.easyfix.ie/ (Ballinaloe, Galway) Brownes feeds in portlaoise Ashe Equestrian in Mullingar PJP Rubber - No problem with fitting odd shapes. The mats can usually be cut to size yourself or the mattresses are installed by the company. TRI (Thoroughbred Remedies Ireland) have them priced at some around E47.39 on their website, not sure if they are any good though: [broken link removed] MayoMats (Co. Mayo) Cow Comforts in Belmullet
I'm pretty certain I bought mine here: [broken link removed] (no connection).
Give them a call and they'll send you out a free sample section. I haven't used them as much as I'd have liked over the past while, but they seem sturdy enough, and for the price they cost, pretty damned cheap.
One word of warning, my mats must have come hot off the press as the rubber smell off them was pretty overwhelming in an enclosed room. It took several weeks for the smell to die down, perhaps if there's no rush leave the, out in the rain for a few days when they arrive?
But, as I said, the ones I got have had dumbbells dropped on them (30, 40kg) and no ill effects. Deadlifts, dropping bar back down have caused no problems. One thing I haven't done is fail at clean or snatch, so don't know what they're like with weights dropping from that height, but from how sturdy (and heavy they are) I imagine they should be fine.