Visibly Muslim: Fashion, Politics, Faith by Emma Tarlo is a book that's just been published which explores Muslim women's dress in Britain. It covers many aspects such as politics, identity, diversity and of course hijab fashion! In one chapter, the author looks at the emergance of Muslim clothing brands, such as The Hijab Shop, Elenany and Capsters. And Hijab Style gets a mention on page 225 too :)
Having read through most of the book now, I'd highly recommend it to anyone interested in Muslim women's expression of faith in the UK. I was especially interested in the section where Tarlo discussed the famous case of Shabina Begum, who wanted to wear a jilbab to school. You can also check out Muslimah Media Watch's review of the book here.