The digital collection Lions led by donkeys has been created by John Bourne at the Centre for War Studies, University of Birmingham. The collection contains concise biographies of British officers with the rank of brigadier-general or higher who served with the British Expeditionary Force at the Western Front between August 5, 1914 and November 11, 1918. Its aim is to show the wide variety in personal and professional qualities of British generals beyond the famous and infamous among them. At present 1,257 biographies can be consulted. You can access them using seven preset sections in alphabetical order. There is also a list of British generals.
The Centre for War Studies has a valuable links section concerning the First World War with much attention for British army units; its variety makes it into a concise web directory.