I don't give a fig about southern party (4)
I believe the answer is:
Here is my best explanation:
'party' is the definition.
(I've seen this before)
'i don't give a fig about southern' is the wordplay.
'i don't give a fig' becomes 'bah' (both are contemptuous or dismissive expressions).
'about' means one lot of letters goes inside another.
'southern' becomes 's' (abbreviation).
'bah' going around 's' is 'BASH'.
(Other definitions for bash that I've seen before include "Party - punch", "Heavy blow; party", "Party; beat", "Social event - clobber", "Attempt", "Party (colloq.)", "Go", "Party - clobber", "Strike hard; party" and "strike".)