The attendants, without exception, having their wits about them (3,5)
I believe the answer is:
all there
'exception having their wits about them' is the definition.
I don't know anything about this answer so I can't judge whether it can be defined by this definition.
'the attendants without' is the wordplay.
'the' becomes 't' (the is pronounced as a 't' sound in some dialects).
'attendants' becomes 'allhere' (I can't explain this - if you can you should give a lot more credence to this answer).
'without' is an insertion indicator.
't' placed within 'allhere' is 'ALL THERE'.
Can you help me to learn more?
(Other definitions for all there that I've seen before include "rational" , "Completely sane" , "on one's trolley, presumably?" , "Not twenty-three [OUT TO LUNCH]" , "Nothing lacking, perfectly sane" .)