I am aware this is in a couple of weeks and I am not suggesting this year but looks like a well organised, regular event that could be aimed for next year!!
Just Walk is an exciting sponsored UK charity walk for anyone wanting to fundraise for the charity of their choice. This fundraising walk is open to charities and anyone who is keen to get their walking boots on and hike for charity - you can choose either 10km, 20km, 40km or 60km routes - so something for everybody. This charity walk offers enthusiastic walkers the chance to experience a breathtaking charity walk over the picturesque South Downs in West Sussex and generate funds for their chosen charity.