St Paul's as well. That's visible from up at Hindhead.
Never realised St Paul's was large enough to be seen so far away.
I've seen other features of the London skyline from Hindhead, but never St Pauls.
Oddly even though I first went up there in the 80s (summer 1984 I think) I never saw London - but perhaps there just weren't enough skyscrapers for it to be prominent.
The only Telegraph Hill I can see on the OS 1:25000 of that area is south-west of Fernhurst. It seems to be wooded and the only close approach is via a private drive. It's only 207m high though. The map marks a viewpoint about 1/4 mile south at Woolbeding Common.
I believe Haste Hill just south-east of Haslemere centre was the next semaphore station towards London. It also seems to be thickly wooded and a similar elevation.
North from there the next semaphore station was at Banacle Hill near Brook. There are good views from nearby but nothing particularly spectacular or unusual.
The two highest points I know of in the area are Blackdown - south east of Haslemere at 280m max; and Gibbet Hill - east of Hindhead at 272m. The former has views south and east to the South Downs, the latter has views north and east to the North Downs and Greensand ridge.
@Taunton said above that St Paul's is visible from Hindhead - I've never seen that far myself but maybe I'll try to get up there with a long zoom and binoculars next time we have a clear day.
This area I do know well.
Telegraph Hill is indeed further southwest, roughly between Haslemere and Petersfield but about 5 miles SE of the railway line. The actual summit is in a private field but you can get fairly close to it on a nearby footpath, just to the west. Views are somewhat restricted due to trees: the best viewpoint in the area is Older Hill, around 0.25 miles further west on open heathland. This gives extensive views of the South Downs and east Hampshire hills, though no very long-distance views.
That said Telegraph Hill is quite a prominent feature in the area, as it's the highest point on the greensand ridge which it is part of, and said ridge abruptly ends just to the west, so it's clearly noticeable as the western end of that ridge. The eastern end of this ridge, Bexley Hill, features the Midhurst TV mast. This is part of the greensand ridge which runs just north of the South Downs, though the ridge becomes very hard to discern further east, and is, overall, much less prominent than the equivalent ridge which is just south of the North Downs, and which features Leith Hill.
Blackdown is the highest point in Sussex and third-highest in southern England from Berkshire eastwards (Walbury Hill and Leith Hill being first and second).
While having a wooded summit plateau it features several viewpoints on the edges of the summit area, notably "Temple of the Winds" to the south, featuring an extensive view of much of the Downs and Weald, as far east as the Lewes area.
There is also an extensive viewpoint on the west side of the hill from which you can see the Downs around Butser Hill and large parts of the Hampshire chalk plateau. The Isle of Wight is visible if you leave the path and head a little west of the viewpoint. I have the feeling the Hannington mast is visible from there though would have to go at night to be sure (the lights are more prominent than the mast itself).
More recently, areas of trees have been cleared on the north side of Blackdown which has opened up views towards the Surrey Heath area, the North Downs and also, IIRC, the Chilterns.
I don't think London is visible though. There are some viewpoints on the east side from which you can see the North Downs around Guildford but have never noticed any London features so guessing the Surrey hills get in the way.