It's a losing battle I fear...
As I said in a previous post, and others have noted too, there are plenty of alternative places to park up, either in Swanage itself, Kimmeridge Bay, Studland etc to name a few.
If I lived in Swanage no doubt I would have a different view, it can't be much fun having loads of 'Great Whites’ and campers parked up everywhere when you simply want to go into town to do your food shopping! That said, all visitors spend their well-earned in the town, so it helps the local economy.
Local councils are generally a law unto themselves, however they have to generate income from somewhere, sadly the odd camper/caravan/great white will spoil it for the majority and they will slap on the fees and restrictions to generate the extra cash.
Either way, I wouldn’t want to park on the seafront at Swanage anyway! The pavement between the road and the beach is less than a metre wide, so not only are you at the mercy of day trippers with their buggies, bikes, scooters, surf boards and goodness knows what else, all ready to scratch and dent your pride and joy (without a care in the world)
you are constantly gawped at as you try and enjoy the view with your cuppa and chips!!
No thanks. Peace and quiet at Kimmeridge Bay for me, all. day. long.