This: “As Alan has pointed out, what we were opposed to was the Suffragette demand for votes for women on the same terms as it then was for men. This, on the grounds that it would have meant more votes for members of the propertied class than for workers”, contradicts this: “As to universal suffrage, we weren’t against this but argued that it wasn’t necessary as enough workers already had the vote that could be used to win control of political power to bring in socialism”. How could granting voter equality (between the sexes) have ONLY increased the size of the bourgeois electorate but not the proletarian one?
The SPGB SHOULD have advocated universal suffrage because that was (and still is) the best way for the proletariat to peacefully and democratically create a free association.