A nice looking set, I'm afraid I can't help with maker though.
They could be 50s or maybe earlier, they have a bit of a 30s look to them, it would be interesting to check if they were Uranium glass.
There probably would have been six glasses, though this is not always the case. Jobling, for example, catalogued their 4050 Lozenge pattern set as consisting of a jug, a tray and three tumblers.
Steven