Looking through an early Percival Vickers pattern book which is full of stemware, there are several with the same type of stem. They tend to be earlier, perhaps 1845 to early 1850s, bearing in mind the factory opened in 1844. Each of them has 6 flutes of varying height on the glass. Not a direct match, but my point would be if all catalogues from this era had survived you would be looking at a few dozen near identical shapes and wondering which was yours.