Have to agree warnbro in wa is pretty good but no facilities. and better still its not so frantic as swanborne is. Unles you ahve private transport getting there is a real pain.
Maybe do a goole search that should give you some friendly ideas but can't think of anything off top of my head
like tilpi I'm based in wa but up in the hills so beaches are a rarity for me, but get to them when I can.