The colour selector and touch control settings appear in a small hole on either side of the keyboard and are changed by a switch underneath the machine (below)
The serial number on this model, which was launched in April 1968, is 7F07049, which means it was made later in 1968. The sequence for the model is: Series I - 7F0001 (1968), 7F38741 (1969), 7F83182 to 8F20392 (1970); Series II - 8F20393 (1970), 8F30940 (1971), 8F81686 (1972), 9F25219 (1973).
Donald Lampert, below is the powder blue monster you asked about, the Model 80's immediate predecessor, the Model 70, which was made by Imperial in Leicester (first in 1962) before the Litton takeover in 1965. According to Beeching, however, it continued to be made until 1968, when it was succeeded by the Model 80. The carriage can be removed, but it doesn't appear to me to be a true demountable like Models 50 through to 66 (55, 58, 60, 65).
Below is the original Imperial standard, the Model 50 of 1927-55. Imperial itself made one electric standard (ELA-ELF series, 1960-67), and under Litton's ownership the Models 660 (1967-71), 777-775 (1970-71) and 790 (1972). These Litton machines also appeared as Royal electrics: the 660 was also the Royal 660, the 775-777 was the Royal 560 and the 790 was a variation of the Royal 970.
Most of these Litton Imperial-Royal typewriters, including the Imperial Model 80 manual, were designed for Litton by Carl Louis Otto (February 24, 1911-April 1983), who was born in Madison, Ohio, and was trained as an engineer at Michigan State University.
Carl L. Otto
He began his career as a draftsman with Duesenberg in Auburn, Indiana, then went to New York to work for Norman Bel Geddes. He joined Raymond Loewy in 1935 to work on Pennsylvania Railroad designs and opened Loewy's pre-war office in London in 1938, which he ran until 1940, becoming a Loewy associate. One of his Loewy accounts was Standard Auto (Triumph). Another was Coca-Cola, which in 1947 debuted a new soda-fountain dispenser designed by Otto and Clare Hodgman for Dole Deluxe. Otto resigned from Loewy's office in 1951 and opened his own firm, with offices in New York, Stockholm and London, which closed in 1954. His best-known designs during this period include the 1951 Schick Model 20 electric shaver in collaboration with Norman Gray, chief engineer at Schick. He reduced the bulk and length of the shaver by rearranging the internal components from the traditional "in-line" configuration to a more compact, wider shape more easily held. The design became the typeform for shavers thereafter. He also designed the 1952 Edison Voicewriter. Both of these last designs won national design awards by the Industrial Designers Institute .
Otto's Imperial 80 design was very influential, including for Olympia (Alfons Boothby and Georges Joseph) and also for Litton itself (Toshihiko Sakow with the Royal 970 of 1972, which was made in Germany).
Wikipedia says the Imperial 80 is a Royal design, but the closest I can find among Royal manual standards to the Imperial 80 are the 440 of 1966 and to a lesser extent the 470 of 1972 (above and below. the latter from Tom Furrier.)