I've just seen this website - http://winstainforth10.foliosnap.com...nels&thumbs=ok
with pictures of some of the abandoned bits of Euston. But there's one
photo - http://winstainforth10.foliosnap.com...tunnels&img=27
- which says that there was originally a bridge onto the old island
platform for the city branch. I've been to euston, and the "other
side" of that photo is half way along the platform. Supposedly its the
original way onto the platforms rather than the 1910s-1960s entrance
at the west end of the platform, which was shared with the Charing
Cross branch.

The only photos I've seen of the island platform are ones showing the
stairs at the west end of the platform. Does anyone have any old
photos/postcards showing the bridge?