Hi, I have approximately 200m2 of Indian smooth sandstone slabbing outside which becomes dangerously slippery when wet or icy. I require an anti slip paint which is durable and clear. What would you recommend? Can a tester be supplied so I can try on 1 slab to make sure it works? Regards, Gavin Kotlewski Elvstone Back Street Freuchie KY157EJ 07764690569.