Hello again,
exactly; I'm the person from Germany, that contacted nearly all institution somehow related to icing, and in particular helicopter icing comprising the NRC in Ottawa, people from NASA Glenn, and several others. I finally got permission from the Ministry of Defense, UK, to re-use the images in this thread. I asked them who holds the rights for these images, since Boscombe Down does not exist anymore; and obviously they do.
Many thanks again for the efforts of all of you.