Thank you all for the interesting material posted in response to my accuracy question.

After yet more searching, I eventually found this page on Garmin's website [Only registered and activated users can see links. ]

which which states:

"The GPS location accuracy of Garmin handhelds is around 3 meters (10 feet), 95% of the time. This means, at any given time, your handheld will save your location within 3 meters of your actual location."

This rather suggests that the position accuracy is being stated in terms of R95 rather than CEP?