A universal new diet finally prescribed and checked (7)
I believe the answer is:
audited
'checked' is the definition.
(I've seen this before)
'a universal new diet finally prescribed' is the wordplay.
'universal' becomes 'U' (film certificate).
'new' indicates anagramming the letters.
'finally' indicates one should take the final letters.
The last letter of 'prescribed' is 'd'.
'diet' is an anagram of 'dite'.
'a'+'u'+'dite'+'d'='AUDITED'
'and' acts as a link.
(Other definitions for audited that I've seen before include "officially checked" , "Checked (someone's accounts)" , "not cooked?" , "Examined (accounts)" , "Checked books" .)