Hi, I'm new here. About the SN-series, I heard from an old sound engineer that the spy stories may be a smaller part of the real story of usage of these units. They were simply what was used before there was radio mikes in the TV-studios around Europe. Nowadays, the hidden mike-packs use UHF radio directly to the mixer, back then the tapes were dubbed in post production. Makes sense to me, specially the Hi-Fi SN units should have been a good source of sound for this purpose. Sorry, it may not be that all of them was part of a good spy story, but I believe some of them were.
Micke