Sean
Ironically I suspect that WW1 had more of a beneficial impact on his career than the comp in so much as when the war ended there was a need to rebuild a number of courses and then later with the economy tanking there was various courses that got built through government grants as a means of employing labour.
MacKenzie was well placed to take advantage of that work based on what he had done prior to WW1 and that would include articles/mentions in the press such as the CL comp. The publication of his book after the war wouldn’t have done any harm either and we know he used that quite liberally as a marketing tool.
But as I said before, he was swimming in a much smaller pool back then.
Niall