I have seen these in halfords I think, and then similar 5minutes later in the bargain store B&M. I'm not sure if they are what you mean. Hey where interlocking floor tiles for garages but I cannot comment on how durable they were. Much cheaper in B&M than halfords bviously.
I bought mine direct from the manufacturer here in Northern Ireland and saved a fair few quid. They must be made on the mainland too somewhere though may not be local to you. Sorry can't be more helpful.