90 days from today is Sat, 15 February 2020
In essence the Regulation 15 (National form Reg 14) notice has replaced the Regulation 9 notice, and should set out what you are being investigated for. It should also tell you whether or not the appropriate authority (The DCC) is considering the matter to be Misconduct (if proven the upper sanction is a final written warning) or Gross Misconduct (if proven the ultimate sanction being loss of career).
Under Regulation 16 you have the right to make a written response to the Regulation 15 notice. However, you only have 10 working days in which to make your response. Failure to make a response could result in an adverse inference being drawn against you.
It is therefore imperative that if you are served with a Regulation 15/16 notice that you contact a Federation Conduct Rep immediately.