In the UK, there are a number of legal options available to protect grandchildren from harm or danger, including:

1. Seeking a Child Arrangement Order: A Child Arrangement Order is a court order that determines who a child should live with, spend time with or have contact with. This can be sought by a grandparent who is concerned about their grandchild’s welfare, and can give them legal rights to have contact with or care for their grandchild.
2. Applying for a Prohibited Steps Order: A Prohibited Steps Order is a court order that prohibits a parent or grandparent from taking a certain action with regards to a child, such as taking them out of the country or making medical decisions without consulting the other parent or guardian.
3. Seeking a Non-Molestation Order: A Non-Molestation Order is a court order that prohibits someone from using or threatening violence, harassing or intimidating someone else. This can be sought by a grandparent who is concerned about their grandchild’s safety.
4. Reporting concerns to the local authority: If you have concerns about the safety or well-being of your grandchild, you can report these to the local authority. The local authority has a legal duty to investigate any allegations of abuse or neglect, and can take steps to protect the child if necessary.

It is important to note that every situation is different, and what works best for one family may not be appropriate for another. If you are concerned about your grandchild’s safety or well-being, it may be helpful to speak to a solicitor or family law specialist who can provide advice and guidance on the best course of action for your specific circumstances.