The most common and most likely answer to this crossword clue is the 6 letter word GASMAN
I've seen this crossword clue in The Guardian
G
A
S
M
A
N
Buddy explains!
The straight part
We know that "individual doing readings" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case individual doing readings = gasman.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 GASMAN mean?
GASMAN noun- A worker for a company that supplies gas (in the sense of the gaseous fuel), especially one who visits premises to read the meter, test appliances etc.
- A man employed in the manufacture of gas.
- The man who controls the lights of the stage.
- A worthless person (male)