David started the London Bike Hub - one of London's few community cycle workshops - and was a long-term member of London Cycling Campaign, so I am raising money for this charity as it's one we both supported. David died suddenly a year ago from a very rare disease - Toxic Epidermal Necrolysis. Other members on this ride are raising money to support SJS Awareness - a charity that supports research into this disease.  I am paying my own way to Amsterdam, so all the money you donate (minus Just Giving's 5% fee and 1.25% processing charge on credit and debit cards [1.45% for Paypal]) goes to charity.