Test centre starts in leaps and bounds with rhetoric (10)
I believe the answer is:
laboratory
'test centre' is the definition.
(place for scientific tests)
'starts in leaps and bounds with rhetoric' is the wordplay.
'starts in' suggests taking the first letters.
'with' means one lot of letters go next to another.
'rhetoric' becomes 'oratory' (both can mean formal speech).
The first letters of 'leaps and bounds' is 'lab'.
'lab'+'oratory'='LABORATORY'
(Other definitions for laboratory that I've seen before include "Experimental area" , "Place for experimentation" , "Experimental facility" , "workplace" , "Where researchers work" .)