What a great picture of the swansea bar.
Lets use your red dot as a starting point.
As you can see there is reasonably deep water on the right hand side coming along the sea wall to the red dot and the waves here are usually pretty good.
The lighter area across from the red dot is the sand bar. In good conditions and flat water you can cross here but I would get into the routine of not doing it as one day you just need a big wave through there and you will get a breaker and thats not nice.
If you go out from the red dot there is an island. Look at the white tip (on the ocean side) of the island, this catches the southerly swell and from this pic the sea is calm but it still generated a white end on the island.
The warning here is that in a 1-2 metre swell a wave can be generated up to 3 - 4 metres coming around the island. This wave usually dies out half way between the island and the left hand breakwall. In behind the island the water is protected in a southerly.
So if you go out, watch the waves around the island and go slightly left of the island and straighten up you should not have any problems.
Coming in, again dont go to close to the island and watch out for the waves behind you.