Pewter plate found under Welney Bridge

Someone very interesting (she does beach cleanups, makes art with what she finds, and also does embroidery for Norwich Castle) that I follow posted these pictures. I tried looking for information on the plate, got nowhere, and (with her permission and thanks) decided to see if someone here could provide any info and/or clues.

All I know so far is that it’s 31cm, pewter, and was acquired “some time ago” in the UK, most likely near Norfolk. Regarding the place it was found, Google says:
“Welney Bridge, over the River Great Ouse, has a history tied to the drainage and flood management of the Fens in Norfolk, England. Originally a suspension bridge built in 1826 by Capt. Sir Samuel Brown, it was replaced in 1926 by a concrete structure carrying the A1101 road.

The bridge is located near the Ouse Washes, a large washland area designed to manage floodwaters from the River Great Ouse.”

Any leads appreciated!

 

I know nothing...but there are 13 of those stars, suggesting American commemoration of some sort, or simply place of origin.

 

Crossed arrows could be an indication that it has something to do with St. Edmund.
https://visit-burystedmunds.co.uk/blog/american-connections

 

You don't mention if there are makers marks. Pewter often has them though they can be very difficult to see.

I have quite a few reference books on pewter marks if you can locate any.

Out of curiosity, what exactly are the light areas (stars, arrows etc) made of?

 

Unfortunately, I don’t know. I’m going to ask the woman who owns it to take a few more pictures, hopefully including both a closeup of a star and one with the tape off the back so the whole back is visible. Thank you for your help!

 

I am inclined to think that it is something to do with witchcraft..Pentagrams, thirteen of them, the crossed arrows are I believe an occult symbol. Maybe the initials of some ritual, or a coven member. perhaps it was buried as part of a curse?
That would be my guess.

 

Are the initials AMT or ATM? The latter would be fitting - bust out another thousand via Automatic Teller Machine to pay for the metal detecting or mudlarking hobby. It costs a b.o.a.t's worth.