hello ...as rosie has indicated, images of clear/cut/etched glass are improved enormously by using a plain unfussy background. From what I can see, the decoration doesn't appear to be etched, but looks to be wheel engraved - although that won't help with dating or provenance, unfortunately.
The signature looks to be unusually neat in its curves - has this been produced in the same way as the wheel engraving, do you think - or might it have been acid etched? Does it have depth like the engraving, or is it flush with the surface of the glass?
From a safety point of view, is there an earth provision in the wiring - if not, then this might have been a dodgy purchase (I'm not suggesting it was, just that should anyone decide to use the lamp then an earth wire is essential in view of the glass and metal).
Was the lamp acquired from within the U.K.?