UK Passport: Emergency appointment (supporting documents)

I asked What is the fastest way to get a UK passport? yesterday. (27/04/17) and the results of that was:

I have booked an appointment for a 1 week emergency passport. I'm currently filling out the application form to take to the interview with me (29/04/17) and I really don't want to get this wrong (as I'll be traveling to London from Nottingham).

Documentation (thus far)

• I have two identical photos which abide by the guidelines set out by 'Her Majesty's Passport Office' with a countersigned signatory (from a professional person who has known me for at-least two years).
• I have also collected a paper application form from my local post office.
• I have the appointment reference number which will help me gain access to the Passport Office.

The Confusion

• The gentleman at the post office said I won't require any supporting documents as I have had a passport previously and my details haven't changed.
• The guidelines set out in Guidance For Attending Urgent Appointments says the opposite:

• All supporting documents - Current Passport, Birth/Marriage/Civil Partnership Certificates or Deed Poll Confirmation etc.

Question

Will I be required to take any supporting documents with me to the interview, if so, what will I be required to take?

The booklet doesn't really specify much on supporting documents except the aforementioned block quote.

Notes:

• I have had both a child passport and an adult passport previously.
• I have the child passport details i.e. passport number etc.. (which is clipped/expired) but not the physical passport (in a different city in the UK).
• The previous UK adult passport was lost.

Update:

I didn't need the appointment reference number to access the building, just my surname and date of birth. Also, I advise you to go into the building atleast 15 minutes before your appointment as you queue up to go through a security checkpoint at the entrance.