ANTIQUE LIDDED POTTERY JAM JAR

In the style of ROYAL WORCESTER, I bought this at a thrift shop for $0,50c,it has a chip to the rim and bad discolouration to the body,would
be delighted if someone can shed some light on this piece as there are no factory marks, except for a gold M or W,the design is oriental,a painted pagoda,chrisanthemums,stylised flying birds,etc.
there are 2 sets of numbers on the base,1 has an alphabet prefix,
b 3026,0 could be a 6 as well,any light shed on this item would be highly appreciated as always.