Hi. Hoping someone might be able to help identify this blue jug. Measures 23 cms tall and the 'bulb' at the bottom is about 11 cms in diameter at the widest part. Weighs just over 700 gms. There's a ground out polished pontil on the base. I've seen something similar on the web described as Whitefriars but I've been through my books and cannot see anything in those so I've discounted Whitefriars as a maker (but am happy to be corrected on that). If anyone can help it would be much appreciated.