Climbing frame used by playmate's pal I erected (8)
I believe the answer is:
'climbing frame' is the definition.
'espalier' can be an answer for 'frame' (espalier is a kind of frame). I am not certain of the 'climbing' bit.
'used by playmate's pal i erected' is the wordplay.
'used by' says the answer is hidden in the clue.
'ESPALIER' is hidden in the letters of 'playmates pal i erected'.
Can you help me to learn more?
(Other definitions for espalier that I've seen before include "Trellis for training fruit trees" , "Lattice-work for training trees" , "Trellis on which shrubs are trained, like pearlies" , "Tree trained against a wall; pear lies (anag.)" , "fruit tree forced flat" .)