Adding light below in an elegant way should not be so poorly executed. The frame is cast aluminium and the prism is acrylic. Mechanicaly the original deck prisms were destined to leak. They are destined for the scap heap.
It's likely we will revisit this. While this solution has stopped the leaks it is not elegant. Glass prisms are available only they have slighly different measurements. The weather will need to be warm and dry to make the changes to the deck.