Teapot - Need Identified, Valued, Will Sell

Can anyone tell me what I have? I know its a teapot, looks to be coin silver. I think it is 1857, since I found one very close online at the Museum Victoria. If you do a search there for teapot, they have one but not quite the same (its the 1st one that comes up on their site when searching "teapot". Would like to know who made it, and possible value.

Thanks,

Dan