Attempt to secure outbuilding that’s ditched by leather works (7)
I believe the answer is:
tannery
'leather works' is the definition.
(place where leather is processed)
'attempt to secure outbuilding that's ditched by' is the wordplay.
'attempt to' becomes 'try' (I am not sure about this - if you are sure you should believe this answer much more).
'secure' means one lot of letters goes inside another (inserted letters are secured inside).
'outbuilding' becomes 'annex'.
'that's ditched' is a deletion indicator.
'by' becomes 'x' (multiplication sign).
'annex' with 'x' taken away is 'anne'.
'try' going around 'anne' is 'TANNERY'.
Can you help me to learn more?
(Other definitions for tannery that I've seen before include "Leather factory" , "Where hides are made into leather" , "Leather-processing plant" , "Rather like sun lamp, arguably" , "place for skin treatment" .)