Studios of earliest design (8)
I believe the answer is:
ateliers
'studios' is the definition.
(atelier is a kind of studio)
'earliest design' is the wordplay.
'design' indicates anagramming the letters.
'earliest' is an anagram of 'ATELIERS'.
'of' is the link.
(Other definitions for ateliers that I've seen before include "workshops" , "Artists' studios" , "Artist's workrooms" , "Accommodation" .)