I have a stubborn blockage in my kitchen sink drain that won’t clear with a plunger. It started last night after washing greasy dishes, and the water drains very slowly. I suspect the trap might be clogged or there’s buildup further down the line. I’m looking for a professional who can diagnose quickly, use approved tools to clear the blockage, and test that the sink drains properly without leaks. Please let me know your availability, any materials you’ll bring, and an estimated timer for completion. The property is a flat in central London.