Hi Anthony,
You are correct about the cable route for factory fitted bi-colour nav lights on the pulpit. The cable goes inside the tube and exits just above deck level on the port side. It then just passes through a hole in the deck, sealed with mastic, and into the anchor locker. It is then clipped to the underside of the deck, passes through the bulkhead and into the forepeak etc. They did not use a deck gland and you end up with about 30mm of cable showing at the side of the pulpit stanchion.
Hope this helps
Graham Ebb
235/25 Blue Jazz