Thanks for this, John.
Will check on the points you mention this evening.
But, if memory serves, the piece is about 5in high. From the photo, it doesn't appear to have a blue trail around it. The colour 'bleeds' vertically down the rim. Is this significant?
Is it possible the piece is a second? Might that explain the colour/design discrepancies and the unusual base?
It is an Isle of Wight shape, right?