Types of records
Hi Kathryn,
I'm not sure how useful this is to you, but I found this http://www.genuki.org.uk/big/BritMilRecs.html. It talks about the different types of British military records. I thought maybe it could help with your first section on military records as I don't think he's specifically discussing records held at the National Archives.
I was going to suggest fleshing out the section on Canadian military records, but I'm guessing there really aren't many resources on specifically that other than LAC's site. Your wiki's looking great!