If you click here you will find the Benetton store locator. If you then choose United Kingdom from the 'select country' button below the map you can look through the list of cities and find the nearest city to you. Then click the 'find store' button to the right, see how many stores have been located and, on the right-hand side of the page, if there are any stores near your city there should be a PDF which you can open to find the exact addresses.
You can also go to the local store locator and type in the name of your own town - you will then be told if there is a Benetton near you. If there isn't, the link will direct you to the company website, where you can find a complete list of locations.
Alternatively you can shop online - just go to the website, which also has a store locator on it. If you have any other questions you can contact the staff through the website.