The most common and most likely answer to this crossword clue is the 7 letter word PROBATE
I've seen this crossword clue in Financial Times
P
R
O
B
A
T
E
More clues leading to the result PROBATE
- Will’s involved in this legal process?
- Certificate and mug perhaps received by the head
- Chatter about old boy getting certificate
- Will reviewing exploration take a short time?
- Official will copy gossip old boy’s penned
- Crown controls rifle certificate
- Confirmation needed for one to succeed?
- Proof of thorough examination: taking a temperature
- More than likely disabled by England’s proof of will
- Validate will in favour of graduate and retell heartily
Buddy explains!

The straight part
We know that "Will reviewing" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case will reviewing = probate.The cryptic/wordplay part
In cryptic crossword there's often an wordplay/cryptic part as well.This part involves a more complex hint, such as an anagram, homophone, hidden word, etc.
Sadly, We don't have an explanation for this specific crossword clue yet.
What does PROBATE mean?
PROBATE noun- The legal process of verifying the legality of a will.
- A copy of a legally recognised and qualified will.
- Proof
- To establish the legality of (a will).
- A court (tribunal) whose function is to administer estates (property of a decedent) and prove wills