Hi, sorry for the late reply, but here goes...
I had similar concerns about the message I was sending with my business degree when applying last year. I think you shouldn't try too hard to incorporate it in your future studies only to justify the fact that you got a law degree. If you don't want to further use law in your studies (apart from the useful skills you acquired getting the degree), then don't waste too many words on it in your
statement of purpose. Mention why you got it and why you decided not to work in the legal sector and pursue a PhD in a totally different field. It' OK to make a wrong choice in life and learn from it. Adcoms don't want a perfect profile, they are looking for something that makes you special and this will bring fresh ideas and points of view to the department. You have lived, you have done other things, and you have decided that what you really want is an English PhD. That's more than reasonable.
Don't try to second guess the adcoms too much. Think first about how things went and how you made your decision to go for an English PhD. Then think about how to explain it in the best possible way. In my case, the business degree was a mistake (in a way), I really didn't like it, I didn't want to work in the field (I found this out while getting the degree), so that's exactly what I wrote in my
statement of purpose. The only thing you need to keep in mind is not to be too negative about things like these. If you want to, send me a private message with your e-mail address and I'll send you one of my
SOPs to give you an idea of how I incorporated the issue of my business degree.