Siv
Welcome to the forum, you might want to have a look at the following FAQ which explain where everything is
Welcome to Benefits and Work I would write a letter with any additional testimony and the extra evidence, explain what you are sending and why it is relevant.
Try and stick with the format of the PIP2, so Preparing Food first, etc.
Send a copy to the same address as you sent your PIP2
Sending Documents to the DWP or Maximus, ATOS or Capita and take a copy of everything to the assessment and ask the assessor to read it and include it in your file before they start the interview.
Gordon