Identity of 1950s-1960s speedboat



Some time ago I acquired a speedboat with a view to restoration. The boat is about 17' in length, marine ply on mahogany frames, lefthand drive, twin cockpit (fore and aft) with a stern mounted inboard engine and Enfield Z drive. The engine is, I'm informed by the Old Ford Club, from a Zephyr or Zodiac circa 1956-1962, straight six of 2.5 litres, and marinised by Wortham Blake.
The only other identifying marks are the very distinctive steering wheel boss and the name "Coral Queen" found under layers of paint (possibly suggesting an import?)
The steering wheel boss has the word CUSTOM around the lower quarter, one large and 2 small chrome and black shields dissected by red and black wings and surmounted by the letters WC in fancy text. The large shield sits just above the CUSTOM text and the smaller ones sit to the right hand side above and below the wings of the bigger shield. To further the confusion there are 4 chrome 'sputniks'-3 small, 1 larger. Two of the smaller ones sit either side at the bottom of the large shield. The larger 'sputnik' is above and to the left side of the shield and the remaining smaller to the right and above it. Whew!!
Any ideas or information as to the boatmakers name or model type would be much appreciated. (Does anyone know how to append JPEG images to these posts?)