Fish set before queen (7)
I believe the answer is:
grouper
'fish' is the definition.
(I've seen this before)
'set before queen' is the wordplay.
I cannot quite understand how this works, but
'set' could be 'group' (group is a kind of set) and 'group' is found in the answer.
'queen' could be 'er' (abbreviation for Elizabeth Regina) and 'er' is found within the answer.
No letters remain.
This explanation may well be incorrect...
(Other definitions for grouper that I've seen before include "I order" , "A fish" , "that by implication isn't sole?" .)