As far as I know, the 9553 shape was only made in this small size. I also have seen others similar to yours and there always seems to be "something" about them which does not say Whitefriars to me. I suspect they are likely to be Scandi? But have nothing really to back up that theory.
If you had them side by side, I think you would also see a difference in the Amethyst colour in addition to an almost indiscernible difference in shape.
I always find it more difficult to say why something is NOT Whitefriars rather than it is.................had a similar problem this week with someone asking about a knobbly vase which was most definitely not Whitefriars but which was probably Czech...........still hoping the photos will appear on here as I recommended they ask here. Seemed the person was somewhat sceptical of
my reply. LOL!