Outside of registered pieces, Molineaux Webb are not known to have marked their wares bar one example mentioned in Hajdamach's book where a vase circa 1850 had "MW & Co" on the base. There is also a spherical orb late 1880s which still has a sticker on it: "M.W. & Co. Ld."
They also used a trademark circa 1850 of "Carnelian" so if anyone has that marked on a piece of Victorian glassware...