Maggot
The Cake of Liberty
I really recommend London's Lost Rivers by Tom Bolton. It gives directions for walking a number of the Thames tributaries plus has loads of interesting information about the places you pass through and the rivers themselves.
http://www.hive.co.uk/book/londons-lost-rivers-a-surface-dwellers-guide/10370094/
http://www.hive.co.uk/book/londons-lost-rivers-a-surface-dwellers-guide/10370094/
