It's approx 4 miles, that's the length of the section of line immediately next to the sea.
As regards the parallel 'structure' just off shore, I now realise what some of you have been talking about! I've seen it many times before, but I'm not totally sure what it's purpose was. One thing I am sure of, though, is that it's nothing to do with (i) earlier sea walls or (ii) protection for the Brunellian work force when initially constructing the wall. I'd put my money on the old sewage pipe theory, although there's a possibility, I guess, that it might have been an addition to do with 'sand retention on the beach'.
Glad to see the various photos of the engineering trains, looks like the plan is proceeding well. I'm hoping to make another site visit tomorrow morning to check on the relaying near Smugglers Cove.
As regards Sea Lawn Terrace, when I spoke to someone I know slightly, who lives the other side of the breach in Riviera Terrace, he was saying that some of the services had been restored, but not everything, so he was spending some of the day at home, but sleeping most (but not all) nights in temporary accommodation, so I guess that electricity was one of the missing services. What I do know, however, is that NR have been meeting with the residents on a planned basis, several times a week, to keep them in the picture regarding restoration of the road and their services, this also in conjunction with the local Highways Dept and other relevant organisations.
As regards the point about route learning, I doubt that any traincrew who already signs the Sea Wall section will need to refresh. As Big Jim rightly points out, an Operations Briefing document has been sent to all train operators by ourselves. It was put together by FGW in conjunction with NR. The temporary signalling solution will not last for long, but the final decisions regarding configuration and duration haven't been taken yet, that's something that will be finalised early next week.