Agency worker has lots of time for painting technique (7)
I believe the answer is:
tempera
'painting technique' is the definition.
(I've seen this in another clue)
'agency worker has lots of time' is the wordplay.
'agency worker' becomes 'temp' (temporary worker sent from an agency).
'has' means one lot of letters go next to another.
'lots' means to remove the last letter (I've seen 'lots of' mean this (the majority of the word)).
'of time' becomes 'eral' (I've seen this in another clue).
'eral' with its final letter taken away is 'era'.
'temp'+'era'='TEMPERA'
'for' is the link.
(Other definitions for tempera that I've seen before include "vehicle" , "may be useful to artist" , "Artist's emulsion" , "A paint and a painting technique" , "Means of painting - pet mare (anag)" .)