Printing outline variables in a dedicated buffer

Have been trying to print the values of outline-regexp and 
outline-heading-alist using some coloured titles. 

The colours are not taking effect, and the values are all wrong. 


(defface pan-face
  '((t :height 1.2 :weight bold :foreground "#00ff00"))
  "Face for outline-regexp heading.")

(defun pandu ()
  "Print current outline configuration to dedicated buffer."
  (interactive)

  (let ((bufr (get-buffer "Pan DU")))
    (when bufr (kill-buffer bufr)))
  
  (with-current-buffer (get-buffer-create "Pan DU")
    (org-mode)
    (erase-buffer)

    (insert (format "%s\n\n" "* Outline Configuration"))

    (insert (propertize "outline-regexp:\n\n" 'face 'pan-face))
    (pp outline-regexp (current-buffer))

    (insert (propertize (concat "\n" "outline-heading-alist:\n\n")
			  'face 'pan-face))
    (pp outline-heading-alist (current-buffer))

    (display-buffer (current-buffer))))