What’s to understand about what a blue bin or box can contain? We’ve had plenty of information about what is suitable, I would think even the illiterate should understand what can be disposed of.
As for inferring that the Veolia refuse collection employees are illiterate and can’t write properly, I’ve always been happy with the service they have given me.
I just wish they would do the blue collection once a month to save money. If plastic containers and cans are squashed flat they don’t take up much room.