Ineffective drainage on Avalon Lane, leading to severe flooding to private property (20 Avalon Road)

As far as I can see, there is one drain on the upper half of Avalon Lane, which the vast majority of rainwater bypasses. Subsequently, all of the rain water pours down the lane (an immense amount of runoff from the large concreted area with private garages at the top of the lane) and then into our property at the rear (20 Avalon Road). In moderate rainfall, the area by our rear entrance becomes flooded, as does our garden structure, which I'm concerned is becoming damaged by sitting in a constant pool of water. In heavy rain, the flooding extends down through our garden, filling under our decking, which I'm concerned is also becoming damaged. If/when this area overspills, water then floods down the side of our house, making it impassable without boots, and surrounds the front of the property, effectively producing a moat around our home. We are currently laying a new patio and I am also concerned that this is becoming damaged. I reported this incident approximately 12 days ago on the phone and was told I would be contacted within 5 days, but have heard nothing so far. As we head towards even more wet weather, I am desperate to get this issue fixed as soon as possible to avoid further damage to my property and to ensure we can access our property without inconvenience and fear of it getting worse. We need your intervention and advice so that effective works are carried out without passing the issue on to other surrounding properties, and if Avalon Lane is your responsibility (in part or whole) then we need you to act as quickly as possible so that damage and the cost of repairs is minimised. We don't want precious council money to be wasted because action wasn't carried out fast enough.