After following this thread with much interest, I have ordered one. It will arrive in a couple of weeks. I have also bought an aquapack for my hand held GPS, and have taken delivery today of a hand held depth finder. The depth finder has a range of 61m and is rated to 200m. It can also be used as a fish finder. I bought the depth finder as I did not fancy dropping off the Kayak in to water beyond my prefered diving range (solo diver). Just counting down the days now!
This is the depth finder
Norcross Portable Depth Sounder
but cheaper here
Discount FishFinders from JG Technologies