I fish it occasionally so limited info.! Had some great times on marina although hate paying for my fishing! The Tackle Box shop gives useful advice on where to try though.
Saw some bass caught (gillnets) 300yds off the beach at Hove very early in the year, much cursed by anglers pulling in flounders (though they had had bass the week before!) on one of the raised groynes. Looks a promising place though. About 1-2 miles out of Brighton along the prom, big carpark near shops (good Italian restaurant!)
I intend to try the harbour you mention the next time i'm down.