I guess it depends on what kind of help you are looking for. There are a number of books that are available on the subject (at least in the States...), and it pays to check out numerous other coffee shops and coffee shop websites. Otherwise, for more hands-on help, you probably should be looking at a consultant to help you more directly. As another alternative, franchising is also a way to get into the industry, but you'll have more restrictions on what you can and can't do for your franchise.
I guess for starters, that's what I see as your first decision: which of the above routes will you take? If you aren't sure, then you have to start evaluating between a franchise idea or your own idea. After that, then start asking if you want to do all of the leg work, or if a consultant is a better option for you. Start talking to as many people as you can about this, and I'm sure that you'll find plenty who will give you all kinds of advice and help. Cheers!
Seems to me that your only compitition would be Costa. They were everywhere when I was over...only one thing through me off...no one serves drip coffee..ask for iced coffee and you get some pretty funny looks. I can't think of one place that had ice!! :?
Things have moved on. Costa are a (weak) third place behind Starbucks and Caffe Nero who are growing like crazy. How are you going to compete against these guys when they open up next to you? What are you going to do differently? I can think of only a handful of independent coffee houses in central London that are performing successfully (read profitably) against such brand dominance. And most of these only survive because of their food offering.
Research - on the internet, and get the books and videos from Bellissimo, SCAA, NCA, SCAE, etc.
Join the trade organizations.
Go to the trade shows and conferences - the big one is SCAA.org, but coffee fest is useful too. Take the training seminars and workshops at the conventions.
Check out your restaurant association, or at least the US NationalRestaurant Association.
Talk to a foreign franchisor about the possibility of developing their brand in England.