Just the place for a saucy fashion centre (5)
'just the place' is the definition.
I can't tell whether this definition defines the answer.
'a saucy fashion centre' is the wordplay.
'a saucy' becomes 'pert' (I've seen this before).
'centre' means to look at the middle letters.
The middle of 'fashion' is 'h'.
'for' acts as a link.
Can you help me to learn more?
(Other definitions for perth that I've seen before include "Scottish/Australian city", "Australian state capital", "Australian or Scottish city", "Western Australia's capital", "Town at the head of the Tay estuary".)