The one on my old (existing) cable is like the one top right of your photo's, Julian, and fits on the arm okay. Chaz confirms what I thought, ie a decent fit is needed, rather than a rattling one.
Anyway, to recap: my bike is 1965, but the brake cable which is listed, and sold, for that year (part no. 41-8535) appears to be wrong for my bike (too long, ie 39 ins outer cable, and clevis fork a very loose rattling fit on my actuating arm, like about 2mm wider than the arm thickness.)
The old (existing) cable appears to fit the bike fine. It is, I think, about the same length as the cable listed for 1960-64 bikes (part no. 41 - 8505) (32 ins outer cable.)
I wonder if the shorter (41-8505) cables have a smaller clevis gap than the longer (41-8535) ones. I'll phone a dealer on Monday morning and check.
I'm thinking maybe my 1965 bike takes the cable designed for the previous year's bike (41-8505, the 32ins type.) That would seem a bit weird. Why would it be? Phil.