I live just along the coast in Eastbourne but used to live Brighton for 12 yrs.
If you like the pin-up, rockabilly, 50's style etc then Brighton is a great place to shop. Have you tried the Lanes and North Laines for shops and ideas? Being a guy, I'm not very knowledgable on the intricacies of the female fashion side of things - sorry.
Great to see someone else locally into the same sort of stuff though.