No offer of the discount means it is now a total and absolute no-brainer to take them to London Tribunals because the penalty remains the same and there are no additional costs. Even if you lost, you have at least made them do some work for their ill-gotten gains, and also they will have had to pay £30 to the adjudicators.
Can you un-redact everything except name and address, please. This is not a murder trial !