You won't find any wave spots in Perth except for Metts and Scarbs (Brighton) and even then it is pretty ordinary
There is nowhere for offshore except the river or Woodman's Point (no waves)
If you want waves in SE to E wind then Esperance is about it sorry
Flat water spots on the river near Claremont... well, anywhere! Pelican Point (Nedlands) for Easterly to Westerly with some south in it, Lucky Bay (Applecross) for Easterly to Westerly with some north in it