PA back in company before the deadline (6)
I believe the answer is:
yearly
'pa' is the definition.
(abbreviation for 'per annum', meaning 'yearly')
'back in company before the deadline' is the wordplay.
'back in' suggests the final letters (the 'back' of the word).
'before the deadline' becomes 'early' (I've seen this in another clue).
The final letter of 'company' is 'y'.
'y'+'early'='YEARLY'
(Other definitions for yearly that I've seen before include "Perennial" , "Approximately every 52 weeks" , "Every 12 months" , "Per annum" , "Annually" .)