Some more notes about the EMI catalog numbering in Europe during the years 1969-1983 (it is what I know, any help is welcome).
"12A 345-67890"
Yes, 12A is a country code, but not the only country component. 12A refers to the country of the target market. So 1C is for the German market, 2C for the Franch market, 3C for the Italian market, and so on.
345 is a reference to the format of the release. Most likely information for the production plant. What material/density to use, what size/shape as well as information of how to transfer the recorded material into the medium (vinyl cutting, recording to tape). 000 denotes a promo or jukebox record not for sale, 006 and 008 a 7" single (008 might be a different compound; styrene vs. regular vinyl?), 016 a 7" EP, 052 a 12" maxi single. Albums are usually in the 022-070 range, double albums tend to have a first digit 1 and cassettes a first digit 2. When the CD was introduced in 1983, this scheme became insufficient.
67890 is what I call the ordinal number. This one can have a regional component as well. If so, it refers to the country where the song material was originally recorded. Note that this is not necessarily the country the artist is coming from; it's merely an indication of the country of the recording studio.
I discovered the following ranges:
04001-07899 = mostly UK-based releases for the continental European market. Included are releases on EMI's own imprint, plus labels like Apple, Parlophone, (EMI-)Columbia and Harvest.
90001-99599 = refers to EMI releases distributed in license. Included are labels outside the EMI roster (Tamla Motown, Asylum, Chrysalis, Private Stock, ABC/Dunhill, Probe, MCA, Bell/Arista). Also included are non-Dutch releases on the Negram imprint (mostly for Belgium and Germany).
60001-65499 = continuation of above in 1977 after the range was full.
80000-81999 = mostly US-based releases for the continental European market; mostly Capitol.
85000-86999 = continuation, also including EMI America.
82000-83399 = mostly United Artists and Liberty releases.
10000-14999 = France (continued: 72000-72999)
17000-18999 = Italy
20001-21999 = Spain
23001-23999 = Belgium (continued: 19000-19299)
24001-26999 = Netherlands
28001-32999 = Germany (continued: 45000-46999)
33000-33499 = Austria
33500-33999 = Switzerland
34000-35999 = Sweden
37001-37299 = Denmark (continued: 39100-39499)
39001-39099 = Norway (continued 37300-37699)