While I am not that au fair with all the brands you mention, I suspect you will enjoy all the following to a lesser or greater extent:
French Connection, Paul Smith Jeans (normally a department store collection rather than stand along store), Next and the Gap (pitched a bit more upmarket in the UK than in the US). M&S (Marks & Spencer) can be staid, but does also have some good stuff. Also well worth a look is Selfridges (huge, fashonable department store) and the clothing sections in House of Fraser and Debenhams which can have some gems amongst the dross.
There are also some great little shops off Carnaby Street (Soho) (try Kingly Court)and in Covent Garden.
If I think of more, I'll post them.
