The most common and most likely answer to this crossword clue is the 7 plus 6 letter word PREMIUM BRANDS
I've seen this crossword clue in Independent
P
R
E
M
I
U
M
B
R
A
N
D
S
Buddy explains!
The straight part
We know that "reportedly getting top marks" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case reportedly getting top marks = premium brands.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.