I took my 380 Aerotec down there last year and came across a lot of stubborn opposition from lifeguards for launching from beaches. It wasnt because of the fee or who was responsible for accepting it, but more of a safety issue. The lifeguards frown upon motored craft simply because of the management of huge numbers of bathers/swimmers in the water, which is totally understandable.
An isolated laned off area for boats where practicable works elsewhere as we all know. In the end i launched from official harbour's such as Padstow and Newquay and paid the relevant fee with the harbour master. Having said that however, this did not stop me from cruising around to the same beaches and landing!!.........which kind of defeats the object.