I’m starting a new job and am planning to use a few ideas from the place I am leaving when I start. Does my former employer have any copyright over these?

This will largely depend on what kind of ideas you are hoping to take with you, and how advanced those ideas are. If you have developed your idea into a physical creation, it may have become intellectual property ("IP"). Depending on how and when your idea became a physical "invention", this may be the property of your employer, and not yours to take with you to a new role. If you have an idea alone, and not yet a creation, then there will be no IP rights, however, it is still possible that your idea may constitute confidential information, which you may be prohibited from sharing.