BIRCHWOOD ROAD 1. 5005 TQ 56 NW 4/105 Coal duty boundary marker. II 2. Coal duty bounday marker, Erected in 1861 or soon after. Cast by Henry Grissell at the Regent Canal Ironworks. Cast iron. Square post with chamfered edges, projecting cornice and frieze bearing armorial shield. Post set up under the London Coal and Wine Duties (Continuance) Act of 1861.