Since Wissant is located southwest of Calais, there is a strong possibility that we are talking of the same battery.
I wrote in the above referenced thread that "the static version of the 12.8 cm Flak gun did not appear in serial production until 1942. The initial version, mobile, was only manufactured in 6 pieces. Therefore, I suspect that the gun on the picture was one of the mobile ones and other 12,8 cm guns may have been installed as well to form a battery."
If the gun was indeed the mobile version and if there were differences between the mobile and static versions, it could explain the various differences we can see on the Wissant picture compared to the later static version.
Emmanuel
