Thanks to Hanno I found another way of accessing the National Archives' WRM series, whci I used to search by way of the ordinary ArchiviaNet system.
http://data4.collectionscanada.ca/ne...e.html&r=0&f=S
These relate ostensibly to the '500,000th' military vehicle, the CMP which features in Dr Gregg's book. However there are a couple of nice shots in there as well of other vehicles.