Peter:
I've never seen a copy of MacKenzie's report to Lahinch. If the club has it in their archives, they have not chosen to reprint it in their club histories.
As Ally notes, the course that MacKenzie was called in to improve was not entirely Old Tom Morris' work. Mr. Gibson had made significant changes to bring the course closer to the sea -- including the Klondyke. Old Tom had thought the big dunes were too big and too volatile to venture into, past the Dell. Indeed, some of MacKenzie's holes suffered significantly from drifting sand from the beaches -- I had a good tour from the secretary in 1982, and he told me that MacKenzie's original 7th, 8th and 12th greens were changed because they couldn't keep grass on them.
Also, the secretary reported that many of the greens had been flattened by the head professional for many years, who doubled as the greenkeeper. [It was implied that his views of them as a golfer might have impacted his views as to what was necessary to maintain them. Before then, I had never stopped to think that this was probably quite common in the old days, where the professional and greenkeeper were the same fellow -- as was Old Tom himself.]
Even if we had MacKenzie's report, if the club told him in advance that they were not receptive to changing Klondyke or Dell, you might not get his unfiltered view on those two holes.