(aside to Shay: odd how so many people have a problem being gender specific but get really nit picky specific about flags, masts and service units.)

Union Jack is correct, it is an alternate name. I figure if Her Majesty says so, that's good enough for me: http://www.royal.gov.uk/output/page398.asp.

My understanding is that, as a flag, the law is held. Private citizens do not fly the Union Jack. As a design, there is no copyright.