perhaps a little confusion here. Are you saying Duncan that there is a lip or ledge of sorts (internally), about 1 centimetre down from the rim?? - and then the moulding starts. Thoughts were that if there had been a lip at about that level, then one possibility might have been a butter dish. Don't think it is a tea mixing bowl - probably too small, and they were cut glass, usually. Aside from the ground bottom, I take it that the remainder of the body is simply pressed glass?