The above stamp arrived many months ago on a purchase from the UK. Even though I said I don't collect stamps I've kept this one. I love the illustration so much that I just couldn't part with it, at least not yet.
Upon further investigation (Google!) I found a great post on The British Postal Museum and Archive that goes in to detail about this particular stamp, the collection it's from and other Dickens stamps throughout British history. The illustration is by Joseph Clayton Clarke who was know for illustrating the characters from Dickens's novels in the late 1800's.