I'd been watching the contemporary market when SIA first started appearing on labels. Sia covers a whole load of different decorative objects - ceramics, rather effective enormous fake flowers, cushions - soft furnishings as well as hard. Before that, similar sorts of glass were often labelled LSA, and before that, Krosno.
I did have a tiny wonder if this onion might be Mike Hunter, but only for a split second, before I enlarged the images. I really do not think it's Mike's work.