HI Rich I’m guessing a bit here but as the payment is paid when you take delivery of your new car then that is the day and payment rate that applies and not the day you ordered.
I did contact motability who did confirm that the payment is made on completion, which I assume is delivery day. But they didn’t answer my question about whether we have to order from Spring to qualify for the £750 or what the actual date is. They just said the payment is £250! ?