We have a large patio on our back garden which despite regular jetwashing had become infested with black mould which wouldn't come off. Scott from S & E used his strongest normal treatment but it still didn't come off. However, he was determined to crack it, and so after consultation with suppliers, he returned with a new stronger treatment, and this time it worked brilliantly. Our patio is now like brand new. Throughout this process, the making of arrangements etc, and on both visits to our house, S & E were extremely professional and friendly and I can't praise them highly enough. Andy Bunting