Australian model, Mavis, suffered in reversion to former type (7)
I believe the answer is:
atavism
'reversion to former type' is the definition.
I can't tell whether this definition defines the answer.
'australian model mavis suffered' is the wordplay.
'australian' becomes 'A' (common abbreviation).
'model' becomes 't' (Ford Model T car).
'suffered' indicates anagramming the letters (I've seen 'suffers' mean this).
'mavis' is an anagram of 'avism'.
'a'+'t'+'avism'='ATAVISM'
'in' is the link.
Can you help me to learn more?
(Other definitions for atavism that I've seen before include "Reversion to the primitive - I am vast (anag)" , "doing things the old way" , "Reversion to a former type" , "reverting to type" , "In reversion to primitivism" .)