Ok so I grew up in Haverfordwest but moved away after university approx 1,000,000 years ago.
So much depends on the tide at the time. The weir at that point marks the end of the tidal water .. mostly.
With a very high tide the weir gets covered by a foot or two of water in an ordinary tide at high tide there may well be a foot or two drop to the tidal water. At low tide there is a serious (5ish) drop off the weir and nobody would contemplate it on a paddle board.
My sister who is still in H’west tells me that there was serious almost monsoon like rain showers at the time and was stunned that anyone would be paddling a SUP on the Cleaddu at that time.
I know bugger all about kayaking or SUPs BTW.
It is just very sad.