Luke
Head down river a bit and you may find things are a bit easier. Below Teddington, where it is semi tidal, the stream tends to be more manageable.
River Lane at Petersham is a nice place to launch a little boat. Have a look on
www.boatlaunch.co.uk for details (there doesn't seem to be a way to link to the entry, but searching for "petersham" will find it).
John