I agree with everyone, allowing a child to go to the beach for an hour alone is just not suitable at all as first step to independence.
Even going to a manned swimming pool with you out of sight would be better than that!
Beaches are waaaay more dangerous than pretty much anywhere you can imagine. A classic scenario which gets the lifeguards out every year is child on a lilo or little boat or paddleboard who then floats out.
Honestly, he's seven, not even eight. Even eight is too young for you not to be easily available.
Having said that I let my 9, nearly 10 year old go out of sight on the beach, I just sit on it in case of emergencies. She plays with other children and I don't watch every second of that time at all. But the point is I can look up, check ok, walk 2 min, sit back down again and so on.
It makes a huge difference if they are a strong swimmer, if they are anything less than really excellent, again it is baffling why this seems ok.
Good first trips out are walking to a friend's house nearby, walking a few hundred yards to school (you can wait behind), then walking to school, walking to the shops and back again. Basically things where they are gone for 10-20 min and you can check with them it went fine.
I would also go through safety around people you don't know on a campsite- so no going into anyone else's caravan without asking, even a friend/other childs.
Small trips around the caravan site would be fine I think- especially if in a gang with other children.