Said about piece going round (7)
I believe the answer is:
orbital
'going round' is the definition.
(I've seen this before)
'said about piece' is the wordplay.
'said' becomes 'oral' (I've seen this before).
'about' is an insertion indicator.
'piece' becomes 'bit' (bit is a kind of piece**).
'oral' enclosing 'bit' is 'ORBITAL'.
(Other definitions for orbital that I've seen before include "Circular, like the M25" , "Of road, circling a town" , "Gyratory" , "(Of a road) going round a town" , "The M 25, say" .)