Surely this is a lose lose situation. Even if Motability decided to allow a car to be purchased at lease end to keep the peace, or were forced to do so due to contractual obligations, they have every right to set the price and could inflate it to make a point: “Hey, what’s the top book price for this car?” “OK then, let’s stick another five grand onto that and offer at that price!!” Not saying they would, but they could!
Having asked for a purchase price at the end of every Motability lease (out of curiosity more than anything), I’d say that was the approach that they were taking anyway! 😂