Pro-Kleen MY16 Patio Cleaner Simply Spray and Walk Away Green Mould and Algae Killer for Patios, Fencing and Decking 5 Litre Concentrate (Makes 25 litres) : Amazon.co.uk: Garden
GLEAN Green Clean Spray - ALGAE, LICHEN, MOULD & MOSS REMOVER - Ready To Apply, No Dilution Required | DIY at B&Q