Very impressed we put in a small announcement (4)
I believe the answer is:
awed
'very impressed' is the definition.
(I've seen this before)
'we put in a small announcement' is the wordplay.
'put in' is an insertion indicator (back).
'a small announcement' becomes 'ad' (short for advert; 'small' indicates a short form).
'we' placed within 'ad' is 'AWED'.
(Other definitions for awed that I've seen before include "in terror" , "Full of wonder" , "in wonderment" , "Wade (anag.)" , "Inspired with reverence" .)