The most common and most likely answer to this crossword clue is the 7 letter word DECKING
I've seen this crossword clue in The Daily Telegraph
D
E
C
K
I
N
G
Buddy explains!
The straight part
We know that "Knocking down/patio feature?" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case knocking down/patio feature? = decking.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 DECKING mean?
DECKING verb- To furnish with a deck, as a vessel.
- To knock someone to the floor, especially with a single punch.
- To cause a player to run out of cards to draw and usually lose the game as a result.
- (sometimes with out) To dress (someone) up, to clothe with more than ordinary elegance
- (sometimes with out) To decorate (something).
- To cover; to overspread.
- The material from which a deck is made.