https://www.campmates.co.uk/
Last year was the first year I holidayed alone - I was terrified. But this camping holiday, surrounded by other welcoming single parent families was the best. The activities are low key and super cheap (a picnic walk... A trip to go crabbing by the beach) whilst the showers etc are scrupulously clean and there are shops a 5 min drive away.
FYI - I get nothing for recommending these guys. I just want to pass on the confidence and fun time I had.