If this is a ciritical setup then I am sure I can help, I ask if it is critical because there are lots of none marine products out there that you could fit but that would not be reliable.
I've used these GoLight remote controlled spot lights on our last two boats. Very happy and the marine versions are weather proof. I like the remote range of the remote, and the speed of movement can be varied for more precise control. Handy when you'r walking back to a dark boat from a restaurant with the remote in your pocket, or back to a swinging mooring on a dark night. These lights have been popular with security forces.
The Gologht as linked by Froggie is the kind of product I would recommend, there are some cheap alternatives but they are likely to fail at just the wrong time.