Personally I would consider contacting the other water users like the Kayakers and organise a very well thought out "drive" (don't want to write campaign) to get the beach access reinstated. It may just succeed after the local government feels satisfied that they have set an example. You may have to propose to form an club around that particular spot where you guys form a board and descipline your own members. Of course, not a single non-member will be allowed to park and launch there, that will be a key feature of any proposal to get it reinstated. This is what we have done overhere when it comes to kite surfing etc after a few incidents.

Wouter