I have found my postcard from Twists Glass which illustrates two pieces which look as if they're from the same range - neither of them have the flared rim, but I don't think that's an issue. This range, designed by Mike, came in a number of shapes.
It is called "Bi Pods" and was winner of the Gallery Gift of the Year 2004.
Mike's a member here, but doesn't pop in a lot, you could write to him to ask from confirmation of the shape.
http://www.michaeljameshunter.co.uk/