The John Lewis Department Store has been in the town since 1983 after they bought out Welwyn Stores. You'll struggle to write all the things they don't sell on the back of a postage stamp as the store is pretty big and has an extensive range of products. Check out their website below for further information.
The Howard Shopping Centre is a fairly small shopping mall in the very centre of the town next to the railway line. It was named after Sir Ebenezer Howard, founder of the Garden City movement and opened in October 1990. It provides 240,000 sq ft (22,000 m2). of space on two levels: anchor tenants include Marks & Spencer, Boots, W H Smith, Next, Clinton Cards and Monsoon. One of the best shops that I often visit is Maher the Bookseller where they have a very large selection of travel guides.