They came with an instruction manual as big as the car's windscreen of where to fit them for just about every car ever made. After a thorough search, the Croma was not found to be on this list! I was just about to give it a 'best guess' when I spotted another small, less than A5 sheet of paper still in the packaging. The Croma was listed on there.
Here is somewhere to get them on-line cheap, they're twice the price at Halfords and possibly cheaper at your local independent motor factors.