Holy person with top-class car, one in no hurry (8)
I believe the answer is:
stroller
'one in no hurry' is the definition.
'holy person with top-class car' is the wordplay.
'holy person' becomes 'st' (I've seen this in other clues).
'with' means one lot of letters go next to another.
'top-class car' becomes 'roller' (informal term for a Rolls Royce).
'st'+'roller'='STROLLER'
(Other definitions for stroller that I've seen before include "Child's vehicle" , "Walker" , "Pushchair in US" , "One taking constitutional" , "He walks" .)