Pls help me Malteese silver letter opener hallmark？

[andrew12]

Marks look like : “B”“Cross”“917”“S”
Please help me“B”and“S”mean？is silversmith or date or others？
I know Malteese silver often used three standards “F”“R”“M”。But don’t known the letter“B”and“S”。
Thank you very much.

[amena]

This punching system came into force after 1920. The "F" "R" "M" letters that meant finenesse of France, Rome, Malta were no longer in use. The fineness is indicated in arabic numbers (917).The letter "S" is a dateletter, but do not know what date matches. The other mark (partially stuck) is the maker's mark.
Regards
Amena

[andrew12]

This punching system came into force after 1920. The "F" "R" "M" letters that meant finenesse of France, Rome, Malta were no longer in use. The fineness is indicated in arabic numbers (917).The letter "S" is a dateletter, but do not know what date matches. The other mark (partially stuck) is the maker's mark.
Regards
Amena

Thanks.
Others?