Range is the main reason to go for the 40.
On private finance the difference in cost is minimal (like £15) but you get circa 100 miles* more per charge.
So that’s why they aren’t “selling” as many 35’s. At least you will be able to spot the Motability car (using a blue badge is the other clue ?).
*Quoted, in a lucid dream the designer had
"Come on BYD Seal!"