Reverse a tutor suffers making valuable discovery (8,5)
I believe the answer is:
treasure trove
'valuable discovery' is the definition.
(I've seen this before)
'reverse a tutor suffers' is the wordplay.
'suffers' indicates an anagram.
'reverse'+'a'+'tutor'='reverseatutor'
'reverseatutor' anagrammed gives 'TREASURE-TROVE'.
'making' is the link.
(Other definitions for treasure trove that I've seen before include "Hidden delights" , "Discovered valuables" , "stash?" , "asset to the government" , "valuable discovery" .)