Sorry for late answer, very lot of work before holidays and very hot weather!! now on holidays for 3 weeks :slightly_smiling_face:
i discover and don't know why i make a mistake in description of the lever, it's not a "loop" but the securing clamp..:face_with_rolling_eyes:and the specific screw and nut
it's a chromed one but brass under it. if it could help ( same dimensions you mention Steve).
i Email you tomorow with pictures