The London turntable was very odd indeed, and really didnt contribute to the show at all, was just a 'wow' factor back then and something to do in the overture. There is an interesting note in the programs that state that late comers will not be admitted when the auditorium is in motion, lol.
But basically the stage aswell as about the first 5 rows or so were on this turntable, so when you sat in the regular seats you were seeing the set from the back which was very off putting because you were basically looking at the back end of the car and the tyre which seemd to block your view of the stage totally (depending on where you sat. I cant remember if it took the entire overture to rotate or not, there was also that weird circle of lights that started down on stage and rose up to the roof, another pointless thing that at the time was cool to see. When I went backstage I was told of a night when the revolve would not work and they had to hold the show for about an hour to rotate it manually.
The wintergarden had parts taken out (not sure if the actual proscenium was removed entirely though. The boxes were as they were not sold (I dont think) and they had some on stage seats aswell. They said they ripped a hole in the roof for Grizabella's exit but Im not sure exactly where, seems from watching the add that the heaviside lift was infront or at the proscenium so maybe she went through a hole in the arch just before the dome. I dont know why she couldnt have just gone up into the flies.
I think too they painted the whole auditorium black, but not 100% sure. The stage also comes out further into the orchestra and those few seats were reconfigured to be more in the round.
So basically the wintergarden version was wider than the current version
http://www.flickr.com/photos/27199361@N08/ Phantom at the Royal Empire Theatre