Wind, and so on, battered a national park (9)
I believe the answer is:
snowdonia
'national park' is the definition.
(I've seen this before)
'wind and so on battered a' is the wordplay.
'and' means one lot of letters go next to another (I've seen this in other clues).
'battered' indicates anagramming the letters.
'so'+'on'='soon'
'wind' put after 'soon' is 'soonwind'.
'soonwind' is an anagram of 'snowdoni'.
'snowdoni'+'a'='SNOWDONIA'
(Other definitions for snowdonia that I've seen before include "mountainous area" , "alpine region" , "Welsh mountain district" , "National park in Wales" , "Welsh mountain region" .)