I have asked Ruth about this one. She writes:
I have got a few of these EC-L guns, all at the moment from the East- one in Japan, one in Thailand, one in Taiwan (the closest to this one in size to this one). All are gunnades, of what I would call the second degree- not the best castings. No indication of who cast them- I guess it is E and Company, but could be someone EC. The L might be Liverpool, but also could be London as there a few small foundries and ships chandlers supplying guns based round the docks there. Cannot even give you a good date for them, 1820s is best guess, but that is just a feeling. Sorry, gentlemen, to be so disappointing.
Bob Smith (with the help of his better half)