Im a H&S officer at a construction firm and builders merchant one of products we produce are concrete lego blocks approx. 1.8m x 0.6m in size the type you would see in a recycling plant that form walls to separate waste, a customer wants to place an order for some blocks and has requested that the blocks hold a A1fire-resistant classification in compliance with REI 240 standards and are effective for at least 4 hours.

Does anybody know such a firm in the UK who would test and provide this certification ? 

Ive tried 2 companys i have found on the net but they seem rather slow to respond and time is the enemy.