@Azteccamper , yes the CritAir sticker cover all the area's the French law had made so far and will be ok for new zones/citys in the future.
@Jabberwocky , i'm not 100% sure but i'm guessing you need new registration and new stickers .
As far i am aware the German and the French stickers are sold as a one timer and stays with the verhicle/licence plate , so if any of this is changed i think you need to renew the sticker .
UK licence plates rules are diffrent then ours so don't know if there's exeptions .
Have you checked theire website
Edit : the French website (Dutch reading version) says :
"The vignette lasts as long you don't change car OR licence plate "
The German website says about thesame , the sticker stays with the car/licence plate and need a new sticker if any details should change.
The stickers are matched with verhicle details(euro norm) and licence plates , i think if any of this changes there's a new registration needed.