FYi, I did see the great advice by greyheads1 on a previous post.

http://fishwrecked.com/forum/yallingup-2

 This time of year you'll be very very lucky to get a day with a swell under 3m.

Can't say I've caught a whiting along the capes coast (don't target them though) but have caught plenty in Geo bay.

 head 5 mins south to smiths and canal rocks you migh be able to find a little snady patch thats protected from the wibe and swell

Stacks of whiting on the south side (reef side) of Yalls beach immediately adjacent to the reef and to the right of the main steps. I have snorkelled there and seen some real thumpers before (~30cms - though may look bigger with a mask on!!) over summer but not fished for them in winter. As Matt says the swell is usually cranking this time of year so its better to be on the longboard or fishing for tailor at the other end.
If its just whiting you want, a consistent spot is the Meelup stretch. Burley up and use worms or prawns as bait stacks of herring or whiting off the sand patches around the shores, though I haven't ever caught anything of a reasonable size. I have caught cobbler, octopus (yep pretty big as well), rays, salmon and tailor before all along that stretch.

Many thanks gents for the advice. I will report back on my return.

Went to Yallingup and the weather was a disater. Will go back in the near future.