When I placed these four caches I launched my kayak opposite Dacre Gardens about fifteen minutes after high tide at Shoreham - and it was quite a hide tide of 6.5 metres. Please bear this in mind as when I paddled back a couple of hours later they were well out of my reach! When I placed them I could comfortably reach them all from a sitting position in my kayak. Remember, your timing will be crucial which is reflected in the difficulty ratings so check the tide times!
I recommend launching from near Dacre Gardens as I know it is doable and that is where I launch from because that is where I live! This will give you a nice paddle up to the first cache on Beeding Bridge. The easiest place to launch and exit is Adur Rec but that is a long distance to paddle. I have also given coordinates for a possible launch spot in Upper Beeding but I have not tried it. As with most places along this stretch of the Adur launching your craft at high tide will not be an issue but getting out again once the water has receded will be more difficult. Let me know in your log where you launched from and how it worked out for you.
The river can be fast flowing so please take all necessary precautions and preferably do not paddle alone. Have fun!