Indeed. This whole are of box liveries is overlooked most of the time, but is an absolute minefield and a recipe for time travel on your layout if not researched even to a basic level given that we spend huge amounts of time and effort in ensuring accuracy of passenger stock and loco liveries. For example the bauxite GENSTAR livery was so widespread and around for 30 yrs globally, yet was replaced around the turn of this century by SeaCo. Similarly, the original P&O appears to be long gone, (unless you count 45’ boxes) as has CAST and many others, Hornby currently sell the 20ft box in ONE livery of reversed Magenta and white, but I have yet to find evidence of its use in UK, Ireland and possibly elsewhere. The 40ft version can rarely be seen. The enduring liveries of Maersk, Triton, Tex and Evergreen are safe bets for covering a near 40 yr span, albeit with some subtle updates and modernised design of the boxes themselves.