If your sell your products or services to multiple locations throughout the UK then you need to think about how you are going to include this in your marketing. Although the search engines do know which locations are geographically close to each other, this doesn’t always mean your website will get ranked for all the locations you want it to. In order to get ranked for an area you need to have reference to it on your website.
If you are targeting the same products and / or services across England for example, then you may choose to have one website but with different landing pages for each area so you can make the page very specific and have a better chance of being towards the top of the search engine rankings. The conte within these pages needs to be different as otherwise you run the risk of your site being penalised for duplicate content. You will need to rewrite the content and add as much relevant information as possible such as customer reviews from that area and contact details.
You may want to consider using Google Adwords as a way of getting you up the top of the search engines quickly as you can create ads which show up almost instantly.