Boss I initially observed in part of TV Centre (6)
I believe the answer is:
studio
'part of tv centre' is the definition.
(TV studio)
'boss i initially observed' is the wordplay.
'boss' becomes 'stud' (both can mean a metal decoration).
'initially' indicates taking the first letters.
The initial letter of 'observed' is 'o'.
'stud'+'i'+'o'='STUDIO'
'in' acts as a link.
(Other definitions for studio that I've seen before include "An artist may work in this room" , "Building for movie-making" , "Workroom for 27 down" , "RA's workroom" , "Artist's workroom - film company" .)