help with mark

I have set 6 spoons all are English & Sheffield maker seems to be P R Ltd but not 100%
5 of six have different year of which i do not know any except one has the Rossette mark of late sheffield. would it be usual to have differing year marks ? could you tell me what they are please.


silver sp 2 rsz.JPG

That’s PP Ltd. for Poston Products Ltd.
Date marks from top to bottom:
B - 1969,
E - 1972,
F - 1973,
A - 1975.