Engineers face corrective (8)
I believe the answer is:
remedial
'corrective' is the definition.
(I've seen this before)
'engineers face' is the wordplay.
'engineers' becomes 'reme' (Royal Electrical and Mechanical Engineers).
'face' becomes 'dial' (face of a clock).
'reme'+'dial'='REMEDIAL'
(Other definitions for remedial that I've seen before include "'Therapeutic, healing (8)'" , "Intended to counteract loss" , "Concerned with those with learning difficulties, for example" , "Putting things right" , "palliative" .)