Jam Spoon Date, Maker, History Information?

British Silver Reading Silver Hallmarks
#1

Hi,
Please see attached photos for what my mother calls a jam spoon?
Armed with my Pocket Edition Jackson’s Hallmarks I have had no luck identifying the marks.

That leads me to think it is either not silver (no lion or Brittania), possibly silver plate or foreign.

All information appreciated, particularly origin, date, maker etc.

The jam spoon is 15cm long.
P1000173_edited-1.jpg
P1000171_edited-1.jpg
P1000169_edited-1.jpg

#2

The spoon is electroplate and the maker is either James Deakin & Sons or Joseph Deakin & Sons of Sheffield. This link shows the same mark under both names.

#3

925-1000.com/silverplate_D.html