Type of car difficult to park, at first (7)
I believe the answer is:
hardtop
'type of car' is the definition.
(I've seen this before)
'difficult to park at first' is the wordplay.
'difficult' becomes 'hard' (synonyms).
'at first' indicates taking the first letters.
The first letter of 'park' is 'p'.
'hard'+'to'+'p'='HARDTOP'
(Other definitions for hardtop that I've seen before include "Rigid-roofed vehicle" , "Non-convertible car" , "Car with rigid roof" , "Sort of car" , "Type of car with removable roof" .)