Your right about it being as clear as mud but how I see it you should get the £600 however what doesn’t help is the way we are going to get paid in two parts.
Those two parts are, we will get £350 sometime in the next few weeks or so then when your car is returned be it next month or next year you will get another payment for £250 so making up the £600.
This could be what’s muddying the waters as it looks like your only getting £250 when you return your current car but with the payment we should get in advance of returning the car end of the this month / November we get the total of £600.
Those dates of end of month or November are only if you got a Motability online account with your bank details register there but if you haven’t got an account I assume you get a cheque at a later date.
Reading this back to myself its as clear as mud. ?