If I remember rightly the application is just shy of £10,000 including site survey and ecological surveys.
You can see why no one does it. I guess I'll just use the stream as a water resource and fit a solar pump into it to fill a tank for watering the garden and flushing the loos. It's disappointing that common sense isn't applied is certain cases. A pico hydro turbine system on a small moorland stream that is fed by a spring and water run off from the moors and has zero fish in it, clearly isn't on the same scale as a megawatt or even Kw hydro system, yet they seem to have the same survey costs. Oh well, it's not like we have a climate emergency on or anything.