Christine — Thanks for making me laugh :hug:
Ian — easily explained. It was pressed as a tall bowl or wide vase shape, and then, while still hot and flexible, a former was used to invert the edge into a mushroom. Minor differences in temperature and pressure would have had significantly different results, and I would expect the different shapes you noticed.
When you've been looking at glass for some years you tend to ignore the final shape, perceiving the earlier stage in manufacture. So, for example, to me, a Whitefriars Tom Hill five-sided bowl with folded rim is essentially the same as a Whitefriars five-sided vase, and if you know one, then you will recognise the other.
Bernard C.