What Oliver wanted in dining room or elsewhere (4)
I believe the answer is:
more
'what oliver wanted' is the definition.
('Please sir, may I have some more' - Oliver Twist)
'in dining room or elsewhere' is the wordplay.
'in' indicates a hidden word.
'MORE' is hidden in the letters of 'dining room or elsewhere'.
(Other definitions for more that I've seen before include "Additional or larger amount" , "What Oliver wanted" , "See 9" , "author" , "Extra (for Sir Thomas?)" .)