Horn Shape Mark

British Silver Reading Silver Hallmarks
1

Hi everybody. Anyone know this marker? Any information would be appreciated.
Horn Silver Mark.jpg

2

I have a piece of silver plate that has the same mark but is stamped with Birks on it.

Also looking as to what it is.

Thanks

3

I have a piece with this marking as well. Is it Birks? Or is it another maker? Any information is greatly appreciated. Thank you.