How do you "trial" an artificial reef ?
Does that mean if the fish don't go there you hoist it up and put it somewhere else?
Stay away from sand and they would just about have to attract fish and therefore work.
As others have said most of the money will go in BS studies and red tape, probably only enough left to drop 3 bricks over the side.
I think I might trial my own, as many others have already done.