Could you do Swim Serpentine to raise money for the RHN? Sign up here swimserpentine.co.uk/how-enter/online-entry/
The deadline is 15 September, and there are distances for all abilities.
Swim Serpentine is a one-day open water swimming festival staged in the heart of London. Organised by London Marathon Events, the festival is held in and around the beautiful Serpentine in Hyde Park, the venue for the open water swimming competition at the London 2012 Olympic Games.