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Murray Buckman you said: I don't see anything which would have been visible before Saturn, except Ganymede, which was perfectly situated but probably too close to Jupiter to be separately discernable without at least binoculars. 

Murray
That’s the conclusion I came to after looking at some Jupiter websites.  The problem was most said you might see Ganymede with binoculars, but never with the naked eyes.  A few said you might see it in special circumstances, so maybe the special circumstances prevailed.  It was clearly visible like an airliner approaching from a long, long way off with its port landing light showing a lot brighter than its starboard one.
Funnily enough, I had the charity shop 12x40 binocs with me (hardly an ideal size, but hey, what do you expect for £4GBP) to see if they were any good for distance viewing in twilight.  I tried them on Jupiter, but I couldn’t hold them steady enough to see two bodies, and there was nowhere to hold them against.  DaveP