Lilac cup stamped '3' underneath

I have a light purple/lilac coloured cup that looks to be a fatbum shape stamped with just a 3 on the base of the cup. Does anyone know who is likely to have made it? There is no matching saucer with it although hopefully i will find something to go with it. Thanks all

The only earthenware Crown Lynn cups that I am aware of with the impressed numbers on the base date from the very early 1960s. The tulip and South
Pacific (fatbum) cups from then were larger than those that we are more familiar with and the clay body is thinner, lighter. I have such a tulip with the Fleurette pattern. I don't know about the plain colours.

Some vitrified tableware also has impressed numbers, sometimes stray letters. We have not worked out what those mean yet, or the dates in which they appeared.

Carmensandeigo are you able to post a pic of the cup and its base. Is the number impressed into the clay or stamped in ink/glaze?
As Jeremy says, sometimes Crown Lynn stamped numbers and occasionally letters on their cups for reasons as yet not understood.