Here is my take on the situation for what it is worth.
Mr Constable credits McLeod with 6 victories on his web page:
1. The web page says took place on 19 Dec 1917.
This is said to be an OOC victory.
This victory is not mentioned at all in my sources which are 'The Sky Their Battlefield' and
'Royal Flying Corps Communiques 1917-1918'..
Doesn't mean it didn't happen, but it would be interesting to find out where Mr Constable got his information about this victory. My guess would be from George Drew's book 'Canada's Fighting Airmen'..
2. Is a triplane DEST according to the web page. No date is given for this victory. It is said to have occurred sometime in Jan 1918.
As far as I can tell there is no mention of a Triplane victory for Mcleod in either of my sources 'TSTB'& 'Communiques' for January.
Once again that doesn't mean it didn't happen, these two sources do not necessarily list all air victories..
3. Balloon. no date given on web page. Web page says Mcleod shot down the balloon in flames and Lt Key was Mcleods observer at the time.
'Communiques' says the date was 14 Jan 1918.
'Communiques' also says the balloon folded and fell, no mention of flames or any credit for a DEST.
This action gets no mention in TSTB.
4., 5., and 6. (VC action of 27 Mar) web page says 1 of these DEST and 2 OOC if I remember correctly.
TSTB also says 1 DEST and 2 OOC credited.
'Communiques' surprisingly does not mention the incident at all.
Mcleod's VC citation says 3 OOC.
so from my meager resources, victories 1 and 2 from the web page are not mentioned at all.
victory 3 is mentioned, but it is left in doubt as to whether the RFC credited Mcleod with a victory for this action. (Were non flamed balloons counted as victories in the RFC???)
4, 5, and 6, are mentioned almost everywhere with one notable exception.
Thus it is very possible that the RFC credited Mcleod with only 3 or 4 victories, and not six as mentioned in the web page. This may explain why he is not in the grub street publications.
Interesting side note: A. W. Hammond (Mcleod's observer) is listed in the 'Communiques' as getting 2 DEST on 18 FEB 1918 with Cpt J. Allport as his pilot (action not mentioned in TSTB).
If he got credit for these and the 3 in the 27 Mar action, he should be listed as an observer ace.