It's definitely not Bagley (they didn't make pressed glass that early, they were bottle makers) and probably not Sowerby. Doesn't strike me as being Greener either, but I could be wrong about that. Is the picture colour? Transfer or hand painted.
It's also not Mary's coronation, it was George V's coronation. A coronation is a ceremony marking the investiture of a monarch with regal power, specifically involving the placement of a crown upon his or her head, and the presentation of other items of regalia. Mary was a queen consort not a queen regnant.