I posted this for want of something better to post, still some interesting replies.
Mullet do travel up this river but its getting a bit late for them, maybe next summer.
Its mud, it looks like sand in the bright sunlight in the picture.
Its Sussex but it could look like Norfolk.
I found a footpath along it a couple weeks ago, I was thinking taking my beach-caster and some lug-worms, maybe some flatties, if really lucky an odd Bass maybe.
Not sure about coarse fish, possibly some Roach or Bream. Maybe maggots as flatities will take them as well as mullet and if any coarse fish them as well. Thats probably the best answer to see whats in there if anything.The picture is low tide, it comes right up the bank at high. Thats why I think a beach caster as the rod would have to be kept high to fish in the main channel over the bank but I have a 15ft coarse rod, I may try that with a swim feeder at slack high water..Its going to run very fast on the way out.
If I get stuck, its goodbye, just remember I was never ever right and laws of average says I should have been at least once.!!