I have found the consumer Mecca for all things boat related: Davey (www.Davey.co.uk). They have shiny things and stuff made in bronze and copper, they have vents, deck prisms… Basically if you want to pimp your boat with a bit of bling (which I very much do), it is all here in spades.
They have been operation since 1885 and were originally based in India dock, so I imagine it could even be where the original fittings came from. I could probably research this by going back to the metropolitan archives (conveniently across the road from my flat). Note to self to do this. I have the original dimensions for the railings that I want to reinstate so will dig both out at the same time.
“A star on board gives positive energy. It can make good things better and stop bad things getting worse. This bronze star is hand cast and finished to a full shine with a central fixing hole so that it can be secured to any part of the boat.”