I recently came across two road gullies which had been blocked by mud and dirt being washed down the road by inconsiderate builders nearby. I reported this to the council who responded quickly, reminding the builder that they were responsible for keeping the gullies clear of debris, and that if they don't, the Council will clean them up and raise a raise a substantial charge for doing so.
If you see blocked gullies, please report them in any case via the LoveCleanStreets app, but if the problem is obviously caused by inconsiderate residents or companies, then please report this separately, I suggest via your local councillor. In the long term, such action will help to reduce the overall cost to the Council.