It's probably also worth noting that very much more recently, (say within last decade), they have started using more than one shade of blue for the hire fleet.
Not the best resolution, but this from the CRT archives shows a pair of Wyvern Shipping Company boats operating on camping boat duties. The butty is clearly DUCHESS OF YORK, and the motor most likely HEATHER BELL. I feel sure I have seen other colour images from this era, but can;t at the moment recall where. I think this is probably not a bad rendition of the Company colours.
The tug leaving the lock is the SICKLE which we currently own.
Fishery lock, Grand Union, circa 1958.