To answer this question many of the color images of the Aquitania were taken in the mid-1940's or just prior to her scrapping in 1950. The color image shown above is now part of my personnel collection as I purchased it from an Ocean liner dealer a few years back. There are about 12 color images I am aware of yet. The best sill being under copyright by the Illustrated London News of her final voyage to the scrappers.
I have seen that picture of the Aquitania and it is an excellent shot - there was a clipping of it on Ebay not that long ago if i remember rightly.
For what its worth to those who are interested:
Buckley Bent lived at The Parks, Aldington at the beginning of the twentieth century. He was one of the very early users of colour photography. His pictures were taken on 4 by 4 inch glass plates and have all the richness and quality of modern colour slides.
Around 1910 he photographed a number of places in the Vale of Evesham including Seward House in Badsey and his own home The Parks. He had to send his pictures to Lumiere Brothers in Paris for processing. He probably used the Autochrome process patented by Auguste and Louis Lumiere in 1904 and available commercially from 1907