AS you have the Notice to Owner, the discount option has gone, as has their re-offer of it in the letter dated 10th September, so you need to submit formal reps this time, (or pay up, but don't pay yet !!) and if they don't re-offer the discount, take them to London Tribunals. Winning may be difficult, but it does seem really barmy to have different codes for each side of the street. It would be interesting to know whether the parking conditions are different for each code. Has the council lost any money ? I doubt it.