Repair shop led by engineers (7)
I believe the answer is:
restore
'repair' is the definition.
(I know that repair can be written as restore)
'shop led by engineers' is the wordplay.
'shop' becomes 'store' (synonyms).
'led by' says to put letters next to each other.
'engineers' becomes 're' (Royal Engineers).
'store' after 're' is 'RESTORE'.
(Other definitions for restore that I've seen before include "Strengthen" , "Repair, put back" , "Return to original condition" , "Refurbish" , "Repair, renovate" .)