Soldiers pull round to enter towers (8)
I believe the answer is:
regulars
'soldiers' is the definition.
(I've seen this before)
'pull round to enter towers' is the wordplay.
'pull' becomes 'lug' (I've seen this before).
'round' is a reversal indicator.
'to enter' indicates putting letters inside.
'towers' becomes 'rears'.
'lug' in reverse letter order is 'gul'.
'gul' put within 'rears' is 'REGULARS'.
(Other definitions for regulars that I've seen before include "The usual customers, of a pub say" , "soldiers" , "Frequent customers of the local pub" .)