I bought the tankard on the right on ebay recently. I recognised it as being by the same potter who made the puzzle jug. I don't know any more about him now than I did before. His name was P.C. Brown and worked in Gloucestershire. I bought the tankard in about 1970 when I was a student and knew nothing about slipware.
For anyone in London on the week-end of 18th of September there some interesting ceramic event. Of course Hannah is at Ceramics in the City at the Geffrye Museum and there is also the opening of the ceramic galleries at the Victoria and Albert Museum.