First welcome to the forum.
Can you post a pic of the light for clarification?
For the idle issue it may be worth cleaning the
as this can cuase problems like yours also take the
sensor off and give a clean.
For the battery make sure all earth straps in the engine bay are secure, and that the battery clamps are tight and no corrosion present. Also make sure the alternator belt is tight as if loose the battery will not get a full charge.
If the battery problem persists, many auto factors / quick fit / halfords will do a free battery check, it may be that the battery is old and no longer able to hold a full charge.
Not sure re the rattle can you pinpoint the area it comes from, a lot of Clio's suffer from sunroof rattles.
Finally a note of caution. Read the threads in the Clio FAQ regarding bonnet catches, one deals with the problem the other preventative maintenance. If in any doubt over the catch security a renault dealer will check for free.