[78-L] Prefixes on HMV, Columbia, Parlophone, etc.

[bryan at claxtonola.com]

Can anyone explain (or point me to a source that can explain) the various
letter prefixes used by HMV, Columbia, Parlophone, etc. in their non-US 78
rpm pressings of the 1920s, '30s, and '40s? I've begun cataloguing my
British, Australian, and European records and I'm boggled by the array of
single-letter and two-letter prefixes. (Columbia has C, DB, F, etc.; HMV
has B, BD, JK, etc.; Parlophone has F, R, etc.) I assume there must be
some rhyme and reason for the various prefixes, but so far, I can't figure
it out.

Thanks!
Bryan W.