Duncan
I have sent you an IM and I won't get into the general discussion of your posts on here, except to clear up a couple of things.
Mackenzie's early golf
I have recently found Mackenzie's earliest recorded competitive round, dating back to 11th February 1899 when he played in the monthly medal of the Leeds GC, scoring 124 (24) net 100, which was good enough for 8th place. His own writing in Spirit of St Andrews, written around 1933, says that 35 years ago he was first a member of the Leeds golf club, which would put the date around 1898. Clearly he wasn't a very good golfer when he started playing seriously. It is important to know that although Mackenzie was born and brought up in Normanton in Yorkshire, his parents were Scottish and I have no doubt Mackenzie considered himself Scottish too. There were regular holidays in Scotland growing up to the family 'home' in Lochinver in Sutherlandshire. He was introduced to trout fishing at the age of six, and undertook hiking, hunting and other Scottish pursuits. Not all that hard to imagine that golf might have been one of these. Then there is his university years, certainly possible he played golf at Cambridge, and to date I haven't looked for any evidence in that direction but I plan to.
April 1917 in France
The last edition of the Chronology has Mackenzie placed at the camouflage school in London on 17 March 1917 and then on 7 May 1917. The journal entry of David Scott-Taylor has them meeting in France, near Arras, on 16 April 1917. Mackenzie was travelling with another Lieutenant from the Royal Engineers and two sappers, and had a briefing with the local brass. Mackenzie left the next day to go back to England. This fits in quite fine with the timeline, and it is very likely that Mackenzie made such field trips around this time, as the war and the trenches were in France and Belgium not in London, and they couldn't just pull all the men out of the trenches and send them back to England for training, so a lot of it would have had to be done 'in situ'. Here is a note in the Chronology, which comes from the "Camera vs Camouflage" document prepared by Mackenzie and Lt. Klein
MacKenzie gives demonstrations on trenchmaking “to units in the Northern Command, at the Special Works School in Hyde Park, the S.M.E. Chatham, and the other R.E. Training Centres, and in France…”
I hope the above helps put things in context.
Neil