The Circuit of Europe race above had stages from Calais to Dover then Shoreham and Hendon. The photo below shows one of the aviators passing over the wreck of the Preussen. A Calais Chamber of Commerce tug was positioned half way between Calais and Dover towing a balloon to assist in navigation.
http://www.flightglobal.com/pdfarchive/view/1911/1911%20-%200532.html
The British Film Institute would appear to have film of the aeroplanes at Dover:
"ACTUALITY. Scenes from the air race. Main title. "Arrival at Dover courtesy of the manager's A.I.R." Some aircraft are seen taking off, landing and on the ground, interspersed with shots of pilots who have just arrived being greeted by officials and spectators (139). "Scenes at the Brighton-Shoreham Aerodrome." Some aircraft taking off, landing and on the ground (282). "Arrival at Hendon." Aircraft appear out of the sky and the pilots are greeted by the excited crowd (375ft)."
http://ftvdb.bfi.org.uk/sift/title/581121?view=synopsis
Full size image at:
http://shipsintheportofdover.fotopic.net/p65085199.html