Thanks for your comment (merci beaucoup) - no real experience either (seen once in Corsica)!
It was a guided tour with experienced birdwatchers from France, including my friend Philippe Huet who had seen several times both species together. We also think there are two juvenile crakes - one Little and one Baillon's (right), obviously smaller presenting short primary projection, short tail (never cocked up or raised vertically), never pending its wings like Little Crake, broad-billed looking, no red or pink on bill-base at all, having very narrow, buff-grey indistinct (not broad and white) supercilium. It looked like a dirty chick, not nice! The shape and habits (reminding NZ Kiwi
) quite different from Little Crake, which is looking nice, longer, slender and long-necked. See more photos of both birds.