On the South Circular Road, initially, occasionally eyeing display (6)
I believe the answer is:
screen
'display' is the definition.
(I know that screen is a type of display)
'on the south circular road initially occasionally eyeing' is the wordplay.
'on' means one lot of letters go next to another.
'initially' suggests taking the first letters.
'occasionally' means one should take alternating letters (letters taken at regular intervals or occasions).
The first letters of 'south circular road' is 'scr'.
The alternating letters of 'eyeing' are 'een'.
'scr' put next to 'een' is 'SCREEN'.
(Other definitions for screen that I've seen before include "Protect - project" , "Mask" , "cloak" , "Light partition providing shelter, concealment etc" , "Blind - hide from view" .)