Be there at the finish, about early tenish (6)
I believe the answer is:
attend
'be there' is the definition.
(I've seen this before)
'at the finish about early tenish' is the wordplay.
'the finish' becomes 'end' (I've seen this in other clues).
'about' says to put letters next to each other.
'early' says to take the initial letters (I've seen 'earliest of' mean this).
The first letter of 'tenish' is 't'.
'end' put after 't' is 'tend'.
'at'+'tend'='ATTEND'
(Other definitions for attend that I've seen before include "Be present or appear at" , "Go regularly to, church perhaps" , "chaperon" , "Frequent" , "Go regularly to (school)" .)