The Kia Niro rejoined the Scheme on 21st August after a period away. When cars join mid cycle it can throw the manufacturers, their website and especially the dealerships as they they tend to produce literature at the start of the quarter.
The rule of thumb is that if it is showing on the Motability search you can order it. It may be the case that you have to explain this point to the dealership, go armed with the Motability reference no: 689275, this is the number the dealership will have to enter to start the order process.
Good luck.