For what it's worth, here is a link to a 1951 Raleigh catalog on Sheldon Brown's webpage: http://sheldonbrown.com/retroraleigh...and/index.html. Several pages are dedicated to the 'Superbe' models, and pages 12 & 13 list special features of the Superbe. Not saying yours is a '51, but most of these models didn't change much, and maybe you can track down your model. I've had to do the same research to narrow down the year of my Raleigh Sports. Good Luck, Nice Bike!
S