first of all I love that pub!!! second, carnaby st. is full of really expensive and trendy shops. You may find nice stuff there but in my case i avoid going to those places, i guess i'm too cheap. I'd rather go to camden Town, there are these really cool vintage shops where i get bellbottoms and tops for only £2!!! I adore that place. Everytime i get some spare money i go and get me a pair of jeans or incense sticks..
Try Pop - its not just in London either. I don't know the website but there might be one closer than london for you. Its basically retro stuff but you can get the odd "hip" thing in there. Its got cords, its got tshirts, shirts, dresses (if your into that sort of thing) Its a great shop i'd buy all my clothes there if i could! Website is : http://www.pop-boutique.com/