My friend from work lives in tutbury in staffordshire near to the castle. she was digging up her garden to lay out a new lawn and found two of these slabs. She took a picture and sent it to me. A market may have been situated around where she lives.
Do any of you guys have any clues. My friend has them still and would like to know what they were used for etc...

http://www.flickr.com/photos/22755890@N03/2188629657/