@Walter Hinteler,
An aside: when I've been to Sandbanks for the first time, it was just known for the ferry* and as a small "mini-Eastbourne". But you could find a lot of quiet beaches and even more of spectacular nature.
Nowadays, it's just expensive.
*In 1964, I wanted to go on the other side, but didn't have money with me for the ferry ticket. So I swam ... and learnt painfully what "chain" in 'chain ferry' means.