First up,last time I was there,the channel was only there to keep you out of the way of hovercraft,at low water,it is just an expanse of sand,I usually work two hours either side of high water.
As you head in the marked channel takes you to the right of the harbour,as you get closer you will see a sharp dogleg to the left.
Once in,visitors mooring were at the far end near the sea wall,it does shallow if the water level is marginal as you get nearer the seafront,but the bottom is thick mud.
If its a sunny day,it will be probably be busy and you may have to raft up alongside another boat or moor against the harbour wall.
The harbour masters I have met there have always been friendly and helpful.