Frankly I don't even comprehend the request to cover up. If I turn up at a busy beach which is full of textiles, I strip off and then get requested to cover up, that makes absolute sense (and frankly doing something like that smacks of exhibitionism). If I'm at a beach, unclothed, minding my own business (and Hengistbury Head is a huge beach, so you can't tell me it was overloaded with people, like Brighton would be, by comparison) and some twit comes along and tells me (asks me, whatever) to cover up... well frankly I think the naturist's response in this case ("I don't care") is pretty muted, compared to how I'd like to react in the same situation.
Agree with your comment about creepy. The fact he took a photo is crazy. I think he should have received a police warning for that alone. And the council reaction is beyond idiotic.