Sleepy daughter fights — last thing mummy needs (6)
I believe the answer is:
Here is my best explanation:
'sleepy' is the definition.
(I've seen this before)
'daughter fights last thing mummy needs' is the wordplay.
I cannot quite understand how this works, but
'daughter' could be 'd' and 'd' is located in the answer.
'fights' could be 'rows' and 'rows' is found within the answer.
A single letter 'y' remains which might be clued in a way I don't understand.
This explanation may well be incorrect...