Here's how to save taking off the wheel, the wheel arch and the side repeater to clean out your windscreen washer filter or paying a stealer to do it for you (circa £170). Empty the bottle as much as you can, fill it with a diluted solution (about 2 pints will do) of water and 'Cillit Bang Black Mould Remover' (yes, you read it correctly!), leave to soak for 24 hours. Voila! Washers working perfectly!
Martin