They haven't reoffered the discount, so it is a complete no-brainer to take them to London Tribunals as the penalty remains the same and there are no additional costs. I suggest you therefore register an appeal with London Tribunals. At this stage you just say "I rely on my representations to the Notice to Owner". There are people on here who may be willing to act for you at the adjudication. Attendance at the London Tribunals offices is not necessary, you can have a telephone hearing. Do not, however, ask for a papers-based adjudication without a hearing, as these tend to be lost because you cannot put any additional points across, or answer questions.