Yes, it stopped being a "good" show to see and became one of those things that you go to see when in London (the Tower of London and Big Ben) a long time ago.
When I saw it in London ages ago, I got more emotionally involved by reading the souvenir program than I did with the show. And I am a big Agatha Christie fan, too.
"A coherent existance after so many years of muddle" - Desiree' Armfelt, A Little Night Music
"Life keeps happening everyday, Say Yes" - 70, Girls, 70
"Life is what you do while you're waiting to die" - Zorba