I guess one of the reason for that high price is she dragged launching too much. I heard that she started again her collections few times from the scratch, and it postponed her brand launching maybe 2 or 3 years than initially expected. Therefore, she should have kept her employees for 2 or 3 years without any result. (She hired really a lot of people considering the average size of designer brand in London) It would have costed really a lot of money.
I believe positioning her brand on that price really hepled her brand makes profitable at least in short term. We will see how it will affect on long term.