I applied Wet and Forget Rapid to my front driveway (block pavia) 2 months ago. It was not very heavily soiled but I can see no difference whatsoever - the lichen has not disappeared. I have spent £40 on this product. I cannot see how waiting longer will make any difference? I do not feel it is reasonable to have to spend yet more months with a dirty driveway and would like a refund. I can provide evidence of my purchase at Wickes.