Everything you need to know in order to fit a Simplex Juy 543 derailleur.
I was interested to note that you clamp the two cables together to ‘automatically’ (but needlessly) manage the chain tension (see scan 3).
I was also struck that the Simplex Juy 543 ‘cannot be fitted to Simplex Tour de France rear fork ends and this should not be attempted’ (see scan 3 again). I suppose I could have worked this out by thinking of the engineering practicalities involved - but it seems a strange piece of marketing.
Another strange piece of marketing is the use of the slogan; ‘When better gears are made Simplex will make them’. It’s rare that you see a call to defer action.