Geoff,
A wonder job!
A comment about plans/research if I may. I have found that ships were often not built in complete accordance with the original plans. Yards were often given leeway to adjust/modify the original design, while likewise the Navy, be it the RN or the USN,, or whatever, often made changes mid-stride during the build. Hence ships often bore differences from the "official" plans. Another observation, which certainly applied to the USN but perhaps not as much to the RN, was that upon completion and acceptance from the civilian yards,, ships were often moved to navy yards for modifications or the addition for weapons or hardware not available to the builders. Photos are most valuable, but for your time frame harder to find.
An interesting reference for the Invincibles is "British Battleships of World War 1" by R A Burt. It includes two profile plans.
Build on!
Jonathan