I've never had a big problem with a major retailer like Jessops, HMV or the like, but I always check if goods are in stock before ordering.
When I was working in Canterbury I used to use these for taking my deliveries -
http://www.parcelpark.com, costs £1 a delivery but you can collect during the day or after work, and get a text and email message when you parcel arrives.
Not very useful for Dover folks even with a car if you don't intend going to Canterbury, but there's an opportunity here for a local business to become an agent - they get a proportion of the £1 collection charge and extra footfall. One for Roger to pass on perhaps.