The Wetland Centre is in Barnes, SW London. You can catch the tube to Hammersmith then bus number 283 which goes to the Centre itself. Buses number 33, 72 and 209 stop nearby and can be caught from Barnes or Barnes Bridge train stations. Fantastic place if you like birds, obviously, with habitats/ecosystems from around the world. Check their website at http://www.wwt.org.uk/visit/wetlandcentre/