Having sanded the floorboards I now know where the small leaks the previous owner mentioned, very small but in a few places in the kitchen hall way and bathroom some worse than others all coming from the top deck.
When Tino was originally converted Myles the original owner asphalted the deck with roofing felt underneath and a damp course around the edges and screwed metal decking into the asphalt and wooden deck. The damp course has started to crack and has completely split in areas letting in water, water is also being trapped in between the decking and asphalt, the whole floor has to be pulled up and resealed.
Rain water and Sea water
Sea water preserves rain water rots, after taking up the decking the problem is quite clear, the asphalt has blown in areas the screws weakened the strength of the asphalt and the asphalt has dipped allowing water to poll and find it's way into the hallway and kitchen. The deck is on a slant creating weak points along the rotten damp course which is the main cause of the major leaks.