That sounds like fun, Carl. I've always loved messing about with clay. I hope your pot makes it :)
You reminded me that I'd found a weird sherd on a walk the other day so I'm just trying to find out what it might be (definitely not prehistoric I'm sure) and I found these sheets http://leicsfieldworkers.co.uk/fieldwalking/pottery-identification/
which I guess are mostly useful to that region but the flint guide might be interesting to people. People are always asking about flints are they not and I guess they don't vary so much as regional pottery styles.