I came across this by accident and thought it might be of interest to some here...basically it's a list of UK Armed Forces senior commanders from 1900 - the present day. Just go to the directories section at the left hand side and click on British Armed Forces and take it from there
http://www.gulabin.com/
For the Army it goes down to Brigade command level and for the RN it lists Captains of individual warships. The guy must have years compiling it. For the RN it's a really useful list of which warships might have been in service at the start of the Twilight War from an on topic point of view (allowing for Options obviously).