An anonymous source has sent me this information re the Colt course at Saint-Andre in France. This is the translation for Saint-Andre from 1925 Euro golf booklet.
"The golf course was designed by HS Colt in 1921. Its 18 holes are completely
finished, but the current clubhouse is only temporary. Two large valleys
surrounded by high dunes form the golf course, which holes are varied and
interesting. The grass is fine and dense and grows naturally on the
sandy ground. The greens are excellent.
Several known experts among others MM. Mackenzie, Alison, Abercrombie and
Major Guy Campbell predict the future could not be better for this golf
course, which will soon become one of the most beautiful seaside."
So it would seem that Mackenzie saw the Saint-Andre course, or perhaps assisted Colt in its design and construction. Interesting.