Quote: Standee "How about talking to the people in question, telling them you find their approaches and behaviour towards your daughter inappropriate and ask them to stop, if after a few weeks they haven't adhered to your wishes then speak to the Police and make a formal complaint?, also document each conversation you have with them and they have with your child (or other family members).'"
... would seem a good place to start.
Although I couldn't argue with anyone who finds this couple's behaviour inappropriate at best and disturbing at worst.