As I have been researching the war memorials I have found the following sites useful for research.
www.ancestry.co.uk – you may need to pay to obtain some information.
Commonwealth War Graves Commission
War Grave Photographic Project
Bedfordshire Regimental Archives
1914 to 1918 – This is a good site to understand the regiments.
Roll Of Honour – Rolls of Honour from around the country.