Was left holding sprog's head (7)
I believe the answer is:
existed
'was' is the definition.
(past tense of to be - to exist)
'left holding sprog's head' is the wordplay.
'left' becomes 'exited' ('exit' can be a synonym of 'leave').
'holding' indicates putting letters inside.
'sprog's head' becomes 's' (I can't explain this - if you can you should give a lot more credence to this answer).
'exited' going around 's' is 'EXISTED'.
Can you help me to learn more?
(Another definition for existed that I've seen is " Lived".)