Hi Pajo
As Corbyeire has said the flats at one time had a very good reputation. Haven't been back in a few years but in my opinion you would be better off driving straight past it.
As soon as the mackerel are in the marks are destroyed, if you are their early the tinsel tossers will think you know what you are doing and set up each side of you, by the third cast they will either of hit you or cross lined you
As for fish, it is one of the more productive mackerel marks, pollack and wrasse are generally small as when they are caught on feathers they end up not going back.
I have seen a few very occasional rays, dogs, various flatties. I caught a small dab which was bitten in two, probably by a tope
If you are after something decent there are far better marks within twenty minutes drive