Links
Where would be the best place to search for the Daily Mail cards? Well, the first port of call would be to obtain a copy of the premier magazine for postcard collectors Picture Postcard Monthly (PPM)

Among the pages of PPM, you will find names and address of specialist full-time
and part-time picture postcard dealers. Many of them will have Daily Mail
cards in their stock. Each monthly issue features articles by
knowledgeable collectors on various subjects, themes or topographical
interest. (Many of PPM's 'back issues' carry interesting and informative
articles on postcards from WW1.) There is also a calendar in the magazine which gives details of the various postcards fairs to be held throughout the UK in the coming months. .
Days Past - old picture postcards
Are you looking for information about Prisoners of War 1914-1918? You will find it here
Are you looking for information about various categories of picture postcards from The Great War? You will find it here