Father is from Spain? Correct! (6)
I believe the answer is:
Here is my best explanation:
'correct' is the definition.
'father is from spain?' is the subsidiary indication.
'father' becomes 'rev' (I've seen this in other clues**).
'from' means one lot of letters go next to another.
'spain?' becomes 'e' (abbreviation for Espana).
(Other definitions for revise that I've seen before include "Go over study material again", "proof", "Improve, amend", "Go over work again as for exam", "Go over books and notes again to refresh memory", "Swot for an exam", "Go back over lesson", "Change - cram", "Study, learn" and "Amend; cram".)