The project was to design a multiple rocket launch system for the British Army. This had become possible with recent advancements in rockets that had made them more accurate than the area weapons of the Second World War. So with this in mind the British started looking at large calibre unguided rockets. Phase one of the project was finished in 1969, with talks about a joint German and Italian collaboration the following year. It seems that the rocket chosen was the same one as used in Project JAWL, which ran from 1963 until 1968. Foil in turn lead to the RS-80 project of 1974, which got killed off by the United States MLRS system, which had a massively faster reload due to the rockets being loaded in pods.
Consideration was also given to warheads with fuel-air explosive, explosively formed penetrators, minelets and flechettes.
The MICV, if you're wondering is the embryonic stage of the Warrior, and was planned as a family of vehicles weighing about 20-28 tons and came in two versions, one with five road wheels, the other with six.