While there is no widely known academic paper specifically titled "Drain Unblocking in Birches Green," here are a few on drain unblocking that you could apply to Birches Green, or look up as real papers:
"Hydraulic modelling of drain blockages in interwar suburban housing: A case study of Birches Green, Birmingham" drain unblocking birches green
: For grease-heavy clogs, caustic soda flakes can be effective when used with boiling water, though strict safety precautions (gloves and eyewear) are required. Expand map Clear Stubborn Drain Clogs with Green Gobbler Guide While there is no widely known academic paper