ILFORD Colour Film 'D' for use in daylight to produce projectable colour transparencies, became available in 1948 as 20 exposure 35mm film, 10 ASA = ISO speed rating. The film is a non-substantive type (as Kodachrome). Available at first in 18 exposure cassettes, price 73p including processing.
Colour Film 'A' introduced in 1949 for use in artificial light. Initially in 18 exposure 35mm cassettes. Also 10 ASA speed. Price 92.5p including processing.
In 1953, both films were available in 20 exposure 35mm cassettes at £1.8p including processing, postage an extra 1.5p.
Colour Film 'F' for clear flashbulb photography introduced in late 1956. Ilford claim it to be of more 'universal' use, in that it can also be used in daylight with a suitable filter while still having a speed the same as Colour Film D. Without a filter and in suitable lighting, it has the speed of 16 ASA. Nonetheless, Film 'D' is recommended if daylight photography is the primary intention.
By 1955, 'a reintroduction' of Colour Film 'A' is credited with a speed of 16 ASA when used with Photoflood lighting.
In 1956-57 all three Colour Films, 'D', 'A' & 'F', are being marketed, but thereafter Film 'A' seems to disappear.
Colour Film 'D' became available in 36 exposure cassetttes in 1959, price £1.48 and 99p for 20 exposure, including processing. Type 'F' continues to be available in 20 exposure cassettes.
Colour Film 'D' available in the 8 exposure 828 Bantam film size in spring 1959, price 53p including processing, postage an extra 1.25p.
In 1960, Ilfachrome (soon renamed as Ilfochrome) replaces the previous Colour Film 'D' in 35mm format. It is a non-substantive film like its predecessor. Still 10 ASA speed. llford Colour Film 'D' is still available in 828 roll-film. Ilford Colour Film 'F' remains available as 35 film in 20 exposure cassettes.
In 1962, Ilfochrome 32 becomes available with a speed of 32 ASA and balanced for daylight. In 20 exposure cassettes price 22 shillings (£1.10p) and 36 expossure at 32 shillings and 6 pence (£1.63p). Processing included. No other colour reversal films and formats are listed. Cine users have 8mm Ilfochrome 25 (25 ASA).

The pictures below are of an 8 exposure, 828 Bantam size, Colour Film D, as became available around spring 1959.

This film box (F.58 = June 1958), the metal screw top container, the instruction sheet (D.59 = April 1959) and its 'return for processing' fabric bag, have been sent to me by Andrew S Redding (February 2021). Andrew intends to use the film, when the weather gets brighter, and then try processing it to black & white negatives. He scans negatives onto his computer, converting to positives for screen viewing or ink-jet printing.

Wallace Heaton advertised 828 Bantam Colour Film D in its 1959-60 'Photographic Blue Book' for 10 shillings and 7 pence (53p), whereas the box has a pencilled price marked on it of 12 shillings and 9 pence (64p).