Warning signs slow to appear in records (1-6)
I believe the answer is:
l-plates
'warning signs' is the definition.
(I've seen this before)
'slow to appear in records' is the wordplay.
'slow' becomes 'late' (I've seen this in other clues).
'to appear in' indicates putting letters inside.
'records' becomes 'LPs' (LP is a type of record).
'late' going into 'lps' is 'L-PLATES'.
(Other definitions for l-plates that I've seen before include "Signs of a learner driver" , "Cutlery for learning to drive" , "Pallets compulsory for novice drivers" .)