A brochure is not going to carry any weight, you woll have to get over it.
If you had proof at point of sale from Motability website, or Peugeot,s configuration and ordering process, you may have an argument. But Motability,s website specifically states what you order may differ from what is supplied, as manufacturers can change features between the time the vehicle was ordered and delivery date.
Motability know manufacturers change their products constantly and factor that into their contract.