I didn't find the time or energy to finish writing up the final two stages of this project once I'd finished it, which was a shame, as the Semaphore Line proved to be an excellent long distance walk - the sort of walk that really deserves a guide book.
However, I've now (March 2012) added a few notes and photographs to cover the final two days of the walk. If you decide to do this walk, and then want a interesting return walk to London, I suggest following the London to Portsmouth inland waterway, another product of the Napoleonic wars.
I was trying to follow the route of the first sections of the London Countryway (a future project) on the OS 000 map when I spotted a feature marked 'Chatley Semaphore Tower' near the junction of the A 23 and the M 25.
A search of the net revealed that this was one of a series of semaphore towers built to link London to Portsmouth in the early nineteenth century.
Wikipedia says: Lord George Murray, stimulated by reports of the Chappe semaphore [in France], proposed a system of visual telegraphy to the British Admiralty.
He employed large wooden boards on his towers with six large holes which could be closed by shutters.
Starting in 1795, chains of shutter telegraph stations were built along [various] routes.
These were operational from 1822 until 1847, when the railway and electric telegraph provided a better means of communication.The semaphore did not use the same locations as the shutter chain, but followed almost the same route with 15 stations - Admiralty (London), Chelsea Royal Hospital, Putney Heath, Coombe Warren, Coopers Hill, Chatley Heath, Pewley Hill, Bannicle Hill, Haste Hill (Haslemere), Holder Hill (Midhurst), Beacon Hill, Compton Down, Camp Down, Lumps Fort (Southsea) and Portsmouth Dockyard.The semaphore tower at Chatley Heath, which replaced the Netley Heath station of the shutter telegraph, has been restored by Surrey County Council and is open to the public.A semaphore-based successor for the London to Plymouth shutter telegraph chain, branching much closer to London, at Chatley Heath in Surrey, was started but abandoned before completion.Many of the prominences on which the towers were built are known as 'Telegraph Hill' to this day.