Help to identify maker of slipware mug

Hello, appropriately I bought this lovely Coronation mug over the Jubilee weekend. I'm hoping someone might be able to help to identify the maker. It is a studio piece made of earthenware. It is decorated with blue slip with an incised design to the front. There is a maker's mark scratched into the base but I can't identify it. The mug stands 3" tall and it is well made, so hopefully an identifiable potter. Any help appreciated.