A website is a great selling tool for your business. The beauty of selling online is that you can reach people that you may not have reached had you only got a physical store, as location is anot as much of an issue with many products. If the products can be easily posted out then you can pretty much sell to the whole of the UK without having to incur extra costs.
It is important to have a strategy in place to target other areas and how you are going to spend your marketing budget to achieve this.
You may want to start off with smaller areas that may be easier to achieve good results in and then look to expanding to larger cities or counties as these will be harder to rank for as there is often more competition. You will need to ensure that you have content on your website that refers to these areas as this will help to get your website ranking higher if someone searches for a product or service that you offer in that area.
You cannot just duplicate pages and change the location as this can be seen as duplicate content and your site may be removed from the listings or demoted.