Laura is great. She nailed She Love Me. We are do for a Camelot revival and would love to see her play Guinevere.
In the case of this revival, though, I don't think that you replace your Eliza with someone who flat-out looks too old and is not used to playing shrinking Violets, When Lauren says, "Married. To me? Who'd marry me?" You believe in her low self-esteem. It's hard to believe that Laura believes it. People want to root for Eliza so she has to appear rather helpless.
As for trying out a young and fresh newcomer, I'll give you an example. I picked up the Times one day and read a re-review of the Sound of Music revival of 1998. I don't remember who the critic was. Rebecca Luker, whom I had loved in Show Boat, had played Maria but had left the show. This reviewer said that the young girl who had replaced her was an improvement, and went on in some detail why she was better. As most of you probably know, the young girl who took over for Luker was Laura Benanti. I felt so bad for Rebecca having to read that.
Another comment: Michael Buckley of Playbill later wrote that Benanti "was an absolutely wonderful Maria ... As do others, I believe that had she opened in the show, Benanti would have been an overnight sensation."
So go for the sensation, not the safe, when turning over the cast. And even though you're having a great time in London, maybe quarrels between cast members and wholesale changes in cast deserve a little supervision.
So here I am criticizing the greatest director of the first 20 years of the 21st Century.
It's all good. It was a terrific revival and I saw it multiple times, one time sitting next to Lauren's mother. By the time the next major revival comes through I'll likely be dead (or as they say so much more pleasantly these days, I'll have "passed."