We spent £2000 on porcelain paving which at present looks awful. The cement has left white marks all over the slabs which we have spent hours jet washing and trying to scrub off but it still looks awful. We are now waiting for a special cleaning solution which you actually sell to help remove this film. You also sell a porcelain tile sealer to use prior to laying the slabs to help prevent this problem. Thanks a bunch for not telling us all this, we would never have bought porcelain slabs if we knew about this problem and would have bought natural stone which we have used many times before without any problems of cement and grout residue clinging to the slabs!!!!