Len had to return and to help (4,1,4)
I believe the answer is:
lend a hand
'help' is the definition.
(I've seen this in another clue)
'len had to return and' is the wordplay.
'to return' shows that the letters should be reversed in order.
'had' in reverse letter order is 'dah'.
'len'+'dah'+'and'='LEND A HAND'
'to' acts as a link.
(Other definitions for lend a hand that I've seen before include "Provide help" , "temporarily transfer an employee" , "To assist" , "Give assistance" , "Pitch in" .)