London’s specialist denim boutique Donna Ida will give you £20 off your next pair of jeans if you trade in an old pair. The best of the jeans they receive will then be styled and sold at their concession in Lily Allen’s new clothes store Lucy In Disguise, which is opening in London shortly. 50% of the proceeds from the jeans will be going to Jeans for Genes, the charity supporting children with genetic disorders.