I purchased a product call SPOT ON Black spot remover and patio restorer. I followed the instructions to the letter. Having followed the instructions I awoke the following morning and the solution had put hairline cracks in 6 of the slabs i had applied it to. I reported this to HOMEBASE who were slow to respond and then passed me on to a company called Sipcam Home & Garden Ltd. Once again these were slow to respond. I provide them with the batch number and all details and asked them to arrange an inspection. I also advised that they carry out a thorough investigation. They eventually came back to me with the following. Sorry for any delay, I have had to wait for the liquid supplier to get back to me and with Easter this has impacted on our response time. Their response was that the active materials in Black Spot Remover could not have caused the damage to these slabs. Even if these are composite slabs made from a mixture of aggregate and concrete/cement, hypochlorite-based chemicals will have no detrimental effect. If an acid-based cleaner has been used, an even surface attack would be expected, removing a millimetre or two at the most. One photo it seems to show that the slab has had impact damage. (THIS IS ABSOLUTE RUBBISH AND THEY REFUSED TO COME OUT AND INSPECT THE SLABS) The product is packed with all its necessary hazard warnings and instructions for use, and precautions that the user must follow. (INSTRUCTIONS WERE FOLLOWED AS I TOLD THEM SEVERAL TIMES) HOMEBASE HAVE CHOSEN TO EXONERATE THEMSELVES OF ANY RESPONSIBILITY. I ADVISED THAT THEY REMOVE THE PRODUCT FROM THEIR SHELVES BUT THEY ARE ACTIVELY SELLING IT STILL. IT IS DANGEROUS.