Unkown Sheffield Spoon? [pics inside]

No one in my family ever thought of investigating the engraving in this spoon, so I’ve decided to gather some info using the internet.
I’ve managed to conclude (again, using the internet) that it’s an English Sheffield silver spoon. However, I’m unaware about the makers identity (RE initials inscribed).
I’m adding a picture and will appreciate any new information to shed light on this piece.

Thank you in advance.
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You have no doubt already found out that the date code is for the 1955/56 assay year. I have seen this maker’s mark in use during the 1950s and 1960s but have not been able to put a name to it.