The most common and most likely answer to this crossword clue is the 5 plus 5 letter word BINGE WATCH
I've seen this crossword clue in The Guardian
B
I
N
G
E
W
A
T
C
H
Buddy explains!
The straight part
We know that "catch a lot on the tube from one sitting" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case catch a lot on the tube from one sitting = binge watch.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 BINGE WATCH mean?
BINGE WATCH verb- To watch multiple episodes of a television programme in a short period of time.