This was used in a popular 1999 commercial for The Gap
titled "Everybody in Cords," promoting their corduroy pants, which come in shades of saffron and yellow. It was also used in a 1987 commercial for a product called Butter It, which is a "liquid butter alternative." In that one, the song was altered, with the line "quite rightly" changed to "just butter it."
Donovan pushed to get his songs in as many commercials as he could, since it was great exposure for them and a nice source of income. How he felt about a liquid butter alternative was immaterial.