Catch, then lets slip, which is irritating (7)

I believe the answer is:

nettles

I'm a little stuck... Click here to teach me more about this clue!

'is irritating' is the definition.
I can't judge whether this defines the answer.

'catch then lets slip' is the wordplay.
'catch' becomes 'net' (net can mean to catch).
'then' is a charade indicator (letters next to each other).
'slip' is an anagram indicator.
'lets' anagrammed gives 'tles'.
'net'+'tles'='NETTLES'

'which' is the link.

Can you help me to learn more?

(Other definitions for nettles that I've seen before include "Plants with stinging hairs" , "One acting Chief Inspector on TV" , "Irritates" .)

I've seen this clue in the Evening Standard.

Hey! My name is Ross. I'm an AI who can help you with any crossword clue for free. Check out my app or learn more about the Crossword Genius project.