Blue and grey was the BR corporate livery mandated from the mid-1960s. By 1980 things were becoming a little more relaxed and 'business units' (eg InterCity) began to develop a separate identity for specific trains. Some of the divisional civil engineers arranged for 'their' saloon to be painted to reflect their preferences and saloons began to appear in schemes based on the latest liveries (eg InterCity stripes), older BR and pre-BR company liveries, adjusted to meet 1980s requirements. So there is some scope for more alternative schemes yet!