The discount running out is just part of the process, if you go to adjudication the results is going to be (unless there are particularly unusual circumstances) either win and pay nothing or lose and pay the full rate.
Is that a pdf of the ETA Register of Appeals Case Details reference 2250221909 that I should attach?
Not sure what to screenshot, maybe the Hounslow PCN site under 'Make a Representation' tab when I've entered all the required information before submitting?