You may need planning permission if you are planning a larger extension. All extensions will need building regulations approval. An architect can assist with this and if planning permission is required. A reputable contractor will also be able to advise you if this is needed as well.
Archway
Archway is a district inside the London Borough of Islington in inner north London. It is situated around the A1 and centred on Archway Tower and tube station. Archway has seven small parks and 2 large parks.
The name originates from the Archway bridge that was built in part of south Highgate for the minor road between south Highgate and Crouch End, Hornsey, in 1896. It had been attempted numerous occasions to make a tunnel for the Highgate bypass, to join the Great North Road by avoiding the steep Highgate Hill and Highgate village's narrow roads. However, these tunnels failed on collapsing.
Archway designates the smaller than 0.4 square miles catchment of its underground station compared to all other stations. The official parishes and neighbourhoods inside its definition are Highgate and Upper Holloway with a little part of Islington. In modern times, Upper Holloway is usually restricted to the smaller sized catchment around its own railway station and post office.
Seven bus routes finish or begin at Archway and the term became popular amongst most Londoners when its tube station abandoned the previous name of Highgate. The Archway Road is part of the A1 or Great North Road, which is among the original toll roads. From 1813-1864, Archway was the location of a toll gate. A plaque on the block of flats at 1 Pauntley Street commemorates the gate.