In reply to Matt Sercombe:
Its been closed for a few years now, and last summer the guides bureau told me that it is closed indefinitely and a new set of ladders had been installed further up the Mer de Glace, to bypass the extremely dangerous area below the Charpou Glacier. These ladders are now the recommended approach to the Couvercle Refuge, (via the rest of the Balcon route) but are extremely difficult to see from the glacier. The previous approach, Les Egralets, is extremely dangerous, bits missing and very unstable giant boulders on the approach, (never again!)
PS, none of the previous or current sections of the Balcon Mer de Glace was proper 'via ferrata', it didn't have cables by the ladders, etc, it was just the same as the usual Montenvers ladders stuff.
Post edited at 17:25