Mike Bryan made me aware that there is a web site devoted to Burge Warren & Ridgley here:
There’s a lot of information on the pens and stylos there and there’s also a book, authored by Mike Bryan and Stephen Hull, entitled The Neptune Pen: A History of Burge, Warren and Ridgley.
It’s heartening to find yet another site on a British pen company. It puts information where we need it, on the web and available to everyone. It can only be good for the hobby.