Vickers Vimy, although a fine plane, is not actually a WWI plane. First 3 Vimys were delivevred 31.10 1918. And only 1 was during the war in France. War ended before it was actually used in strategic bombing.
Well OK. There were 3 Vickers Vimys in the great war, but their contribution to RAF was insignificant. It was only in July 1919 when delivers to RAF actually started.
No offence, but that's what Kenneth Munson's book " The Pocket Encyclopedia of World Aircraft in Colour - Bombers, Patrol and Reconnaissance Aircraft 1914 - 1919 " says.
So perhaps some more numerous planes first?