I had a look at this small concrete overflow with Nckt. The first manhole led to a small chamber with a 3ft pipe and a grill. The second dropped us down into the main pipe on the other side. Immediately downstream was a sump which took the pipe under a brook to eventually outfall into the Mersey.
A short trek upstream through RCP lead to a small CSO chamber with an overflow weir. It wasn't a very interesting explore but still good to get underground.