Hiya Roy , I lived in Hornchurch for many years and the Thames was my nearest water.......
http://www.rib.net/forum/f16/on-any-sunday-44335.html
If you enjoy ribbing in the South East , you will love it from the Solent westwards , adore it in the West ( Pembrokeshire was a regular haunt for me ) and " die " for it off the west coast of Scotland.
My advice to you would be to join any organised cruise by reasonably experienced local RIBnetters . Regards Bern