Interesting,
bill and I got crossed as I was editing. Sorry.
The tiller part of the casting is a very simple shape, and would probably be relatively easy to have recast. It also would be a piece of cake to make a pattern
I will either glue on wood 'ear' extensions to the bronze as suggested and use that as a pattern to be recast
OR make a model out of wood and take that to the foundry. If I made it, I would also widen it to take more tiller width, it is only 1 1/4" in the 'channel' in the original. That's really not enough for a hard working piece of wood!