If it's awkward for you to get to and you still want the job then they will most probably want to be assured that you are going to be reliable if you get the position. If you suspect you will be asked to work at the Wadsley Bridge branch then if you are using public transport plan the trip there before the interview so you would arrive there well before 9am when it opens (10am on Sunday which can sometimes be more awkward with UK transport) and allow for delays (E.g. go for an earlier bus / train if possible), then if they ask you how you intend to get to work each day you will be-able to tell them exactly what bus or train you intend to get and make it sound like it's no issue for you what-so-ever (unless you don't want the job of course). This will go down much better than just answering, "public transport", but I suppose if they haven't even told you where you would be working yet you might not be-able to plan for every possible location. Even if you drive it can go down well if you say, "I will drive", followed by a backup plan in case your car happens to be off the road as this shows commitment.
Think of a good answer to the most obvious questions that will probably be asked like, "why do you want to work for Halfords?" and "where do you see yourself 10 years in the future?" (it might not be exactly 10 years obviously, but you get the drift). In both questions they will be testing you to see if you are serious about working for Halfords and whether you really want the position, or whether you are truly only looking for temporary job for the money until you get something better which is obviously what they don't want (unless it's a Christmas job only or another temp position of course, then they probably won't ask the 2nd question). The 1st answer will probably be something unique to yourself, but for the 2nd question you could say something like, "I would hope to see myself in a supervisor role or even perhaps training for management position". Another common question is something on the lines of, "what do you feel you can offer to the company?", this is usually best answered with something like, "I'm an enthusiastic, reliable and hard worker" and add anything else you feel relevant and good about yourself, this is your opportunity to really sell yourself. You will probably be asked about your experience, if you have none it doesn't rule you out, especially since you've got an interview, but at least say that you are enthusiastic and quick to learn. If you've been out of work for a while they will most likely ask why or what you've been doing for the last so many years, I know it may not be easy, but it's probably best to be honest, the most important thing however is to show them that you're totally ready and fit for work now, and that you're not likely to cause them too many issues. They may also ask you about your last position and why you left which you might want to prepare a good answer for. Finally if and when they ask you whether there's anything you'd like to ask them at the end, always have a good question, it shows you are interested and keen, but NEVER ask about money, asking about future career and training opportunities in the company is a good one (assuming it's not a temp position), if it is a temp position you could still ask about the possibility of permanent positions coming up in the future.
Well done for getting an interview and I wish you the very best of luck!