I'm not sure if their are any there at the moment. All the times I have tried Wivenhoe in the past have been futile. When the, "Tide", was dropping rapidly the weed died off and the catfish slammed every redclaw they could see. And they could see all of them as they no longer had anywhere to hide.
But if you want to give it a go just buy some opera house pots and put some cooked potato in the bait sleve or some meat of some kind and see what happens. You've got nothing to loose by having a go.
Louis