If you had the other boat’s details, I think maybe you should have reported the incident to both your boatyard and the other one. Although not an emergency, (how easily it could have been!) if both boatyards had details they could act if they wanted to. I guess you would have an emergency number to ring although just an answerphone message would probably suffice. On a private boat, a message on BA’s answerphone and one to the hire yard I guess would be the way to go.
Although we hear of, and on the odd occasion see, hire boats navigating after dark from time to time, I can’t recall ever hearing of a serious incident. I hope I never do.