I am under the belief that there was more costal defense's and weapon instilations on the channel islands than the french coast.
You are right Tony the guns where a right mix and match of all varieties and places of origin, the story i have heard about the mirus guns where they where captured then stored in Norway, where they lay forgotten, until an officer remembered them, it was from then they where overhauled and down rated in the explosive charge that could be placed in them.