Mystery mark on brooch?

This one came in a bag lot of mostly silver. It looks more pewter or other white metal to me than silver though. I can’t make out the mark unfortunately. I’m not even sure if the whole mark is visible. Anyone know it?

 

It looks like "By J" to my eye.

Debora

 

Thanks I’m not seeing anything that looks similar in that persons production. This seems like a pretty vintage piece to me. I’m also seeing the mark several ways. One is the way you saw it. The other is lozenge like punches that are slightly worn with letters inside of them.

 

Saint Justin pewter, from memory.

 

My St Justin pewter jewellery has their name and their round knot symbol. I'm not seeing that here.

 

I've got a Celtic style pewter brooch with that mark, which I'd thought was SJ, but I don't have the box any more. Let me go hunt it down....