Hi Jazz,
The pattern book has a number of comports / centre stands from the 1850s. Most of them look quite heavy with a thick stem. The majority of the centre stands are shown with the top detached, and are probably showing an upside down comport with a dish balanced on it. A couple show frosted designs but the majority have cutting in the same ballpark as the photos in this thread - it just so happens that the Oxford Tea Party one looks a little closer to the style. I have yet to see any examples of these 1850s pieces which I would say might be Molineaux & Webb. There is however, one shown on page 27 of the 1978 book "Victorian Table Glass and Ornaments" by Barbara Morris, which is captioned as probably by Molineaux & Webb.