RHM, you are correct in your assertion that it is a post-Raleigh Rudge. I examined the exploded drawings of the model 11 Raleigh (111 Rudge) revealing that it perfectly matched the unit I have. I am glad to finally narrow down the date to at least a ten-year period. I will try using Raleigh frame numbers to narrow it down further. Thank all of you for your help!

I have not yet found the production dates for the 11/111 frames.