Visitors, let's suppose, about to start tea (6)
I believe the answer is:
guests
'visitors' is the definition.
(I know this)
'let's suppose about to start tea' is the wordplay.
I cannot quite see how this works, but
'tea' could be 't' (I've seen this in other clues) and 't' is found within the answer.
'suppose' could be 'guess' (synonyms) and 'guess' is found within the leftover letters.
No letters remain.
This may be the basis of the clue (or it may be nonsense).
Can you help me to learn more?
(Other definitions for guests that I've seen before include "Those invited" , "Folk receiving hospitality" , "Hosts entertain them" , "House or hotel visitors" , "Invitees or hotel customers" .)