Novelist pens mad, inauthentic and pedestrian advice (5,5,4)
I believe the answer is:
green cross code
'pedestrian advice' is the definition.
The definition suggests a singular noun which matches the answer.
'novelist pens mad inauthentic and' is the wordplay.
I cannot quite understand how this works, but
'mad' could be 'cross' (both can mean angry) and 'cross' is present in the answer.
'and' could be 'n' (common abbreviation for 'and') and 'n' is found within the answer.
'novelist' could be 'eco' (Umberto Eco) and 'eco' is found in the remaining letters.
This may be the basis of the clue (or it may be nonsense).
Can you help me to learn more?
(Another definition for green cross code that I've seen is " Set of safety rules".)