[Arran]

Are these FM IF transformers slug tuned or are they the kind with trimmers? If the type with trimmers a small drop of penetrating oil may help get them out if the end of the screw isn't peened over or something. I replaced the trimmer screws in a Philco AM IF transformer and they were a very fine machine tread, I don't know what pitch, I pulled some replacements out of one from a scrapped set, the FM ones may use the same thread pitch as the AM ones, but a thread gauge would be useful for finding out. 
Regards
Arran