Jacek,
Well, I looked again and also took photographs and the letter I thought was an "F" is most probably an "E". I'll keep posting so I can share images...
When the frames were designated SP/SL, which tubes were SP? Only the seat tube or others also?
I found this Eddy locally but it's not my size unfortunately. I also own a Motorola replica TSX that fits and it's a keeper.
Many Thanks,
Chris