Here's a potential cracking little buy from eBay. It is a pair of cut glass custard cups with Greek Key decoration, shown with a pound coin for scale. I think these are by Molineaux & Webb.
Custards & jellies are one area of the MolWebb pattern book where I thought a positive match very unlikely, as virtually all of their designs in this category were cut but with little decoration. One exception though was a custard & jelly set with Greek Key decoration where they called the design "Halifax".
Comparing to the pattern book sketch - which I can't show for copyright reasons - these pieces match on the Greek Key, the style of handle, general dimensions, the style of cutting on the foot, and it's almost a perfect match on the body, where the oval cuts look a little further apart than in the pattern book.
These things will never match precisely as the MolWebb pattern book was not like a catalogue - it's mostly pen and colour wash sketches with Victorian flourishes. Plus there is quite a bit of variability in the pair in the photo. One has a notably larger etched Greek Key design, and the handle is very slightly different. The ovals are also slightly larger size. Still a pair though!
So I'm >90% positive that these are Molineaux Webb "Halifax" custard cups, dating them to the mid to late 1850s. Anyone seen similar in glass catalogues from other companies? MolWebb often get confused with glass from Richardsons...