The British Oliver Manufacturing Company had various European portable typewriters branded as Oliver.
The first portables branded with the Oliver name were manufactured in two locations by two different companies. One of these manufacturers was Fortuna Buromaschinen GmbH of Berlin, Germany. This company was formerly known as Stolzenberg-Fortuna, which used to distrubute Olivers in Germany as the Monopol-Stolzenberg and Stolzenberg. The other company that manufactured these early Oliver portables was known simply as Oliver Typewriter (Italy) Ltd., which was a registered corporation of Italy in 1930.
Between serial numbers 80000 and 90000, Oliver Typewriter (Italy) introduced a couple new body styles. For more information on the various name variants produced, see Oliver SIM MAS by typewriters.ch.
After World War II, the British Oliver Manufacturing Company rebranded a Swiss machine called the Patria. These were branded simply as "Oliver Portable". They were available in black and grey.
Another Oliver portable was branded as the Oliver Courier. In Canada, this model was branded as "Eaton's" and "Simpson's" for their respective department stores. I have only seen the Simpson's in a dark green crinkle finish. The Oliver Courier was also sold as "Conquerer". All of these names mentioned were numbered with the Oliver Courier serial number scheme. This body style was also sold as a Patria, Japy, and Voss Privat. These names were not part of the Oliver Courier serial numbers.
There are two distinct styles of Oliver Courier. One style displays "Oliver Courier" on a recessed badge on the right-hand side of the cover. The other style displays the name centered on the cover. Similarly, the Simpson's variant also has two styles. One displays "Simpson's" on a badge on the right-hand side of the cover while the other has a decal centered on the cover.
The first model of Voss that was rebranded by Oliver was the Voss DeLuxe. This body style was sold as the Oliver Consort. It is distinguished by having individual lids covering the ribbon spools as opposed to a one-piece top cover.
From what I can tell, this body style was first introduced by Voss in 1952 and was manufactured until around 1957. It would be logical that the Oliver Consort was produced around the same time, but possibly not beginning immediately in 1952. I have yet to even find a photo of a known example. The closest I have found in existance today is an Oliver Consort manual.
The Oliver M-Series was likely introduced around 1957, replacing the Oliver Consort. This update occured because the Voss M-Series replaced the Voss DeLuxe. The M-Series is distiguished from its predecessor by having a one-piece top cover as opposed to individual lids covering ribbon spools. I have seen Oliver M-Series models MDT10, MT10, and MT13, which is a wide carriage MT10. Any Voss M-series variation could have been produced as an Oliver M-Series. Note that since the Voss M-Series machines were produced as S-Series machines after the British Oliver Manufacturing Company went out of business, an Oliver S-Series was never produced.
The Oliver M-Series serial numbers appear to be a separate run from the Voss M-Series machines. Unfortunately, since hardly any of these Oliver M-Series portables seem to have survived, the range of serial numbers is uncertain. Therefore, it is also unclear how many were produced. The Oliver M-Series machines were most likely discontinued when the British Oliver Manufacturing Company shut down in 1959, even though Voss manufactured machines until 1965.