That surprises me, given that large logo was not carried by most classes and BR Blue basically was.
I read several anecdotal accounts, over the decades, which suggested that the all-over monastral blue was deemed the spawn of the devil because it negated the thought which had gone into many British Railways era diesel schemes
(maroon Westerns / two-tone green Sulzer Type 2 and Type 4 / EE Deltic two tone green / etc).
As a youngster seeing a monotony of class 45s and 47s, all blue, it certainly seemed dull to me.
Large Logo livery, was seen as a refreshing (and a popular) change, to that dreary all-blue corporate era. Sectorisation took it a stage even farther.