Two places in London are named Telegraph Hill
Part of Child's Hill in the London Borough of Camden was given the name after the optical telegraph formerly sited there - Wikipedia page [1] refers.
The other Telegraph Hill is a largely residential conservation area bounded by Nunhead and Brockley and is an electoral ward just south of New Cross in the London Borough of Lewisham in southeast London, England. Wikipedia page [2] and Lewisham Council page [3] refer.