Climbing frame very badly erected inside (7)
I believe the answer is:
trellis
'climbing frame' is the definition.
'trellis' can be an answer for 'frame' (trellis is a kind of frame). I am not sure about the 'climbing' bit.
'very badly erected inside' is the wordplay.
'very' becomes 'tres' ('very' in French).
'badly' becomes 'ill' ('ill' can be adverbial as in 'ill-advised').
'erected' says the letters should be written in reverse (in a down clue, letters go up).
'inside' indicates putting letters inside.
'ill' written backwards gives 'lli'.
'tres' placed around 'lli' is 'TRELLIS'.
Can you help me to learn more?
(Other definitions for trellis that I've seen before include "Latticework structure" , "Train for plants" , "Framework supporting climbers" , "Framework - stiller (anag)" , "Garden support for climbers" .)