Worry a great deal beforehand what driver may get into? (6,4)
I believe the answer is:
bucket seat
'what driver may get into?' is the definition.
'worry a great deal beforehand' is the wordplay.
'worry' becomes 'eat' (eating is a kind of worrying).
'a great deal' becomes 'buckets'.
'beforehand' is a charade indicator (letters next to each other).
'eat' after 'buckets' is 'BUCKET SEAT'.
(Other definitions for bucket seat that I've seen before include "welcoming structure" , "Low single chair found in cars or planes" .)