Fast vehicle ditched by Shell? (5)
I believe the answer is:
'fast' is the definition.
(apace can mean quickly)
I don't understand how the remainder of the clue works.
Can you help me to learn more?
(Other definitions for apace that I've seen before include "flat out" , "(Move on) swiftly" , "Swiftly, quickly" , "Quick" , "At a rapid rate" .)