diamond and 9 carat gold ring for my 18th birthday! hallmark help!

by Lucy
(Liverpool)

my 18th birthday was a week ago and my mum knows my love of all things antique and old so she got me a rather cute and dainty secondhand diamond and 9 carat gold ring, but i have taken a picture of the hallmark so someone can help me to date it.
it has these inside of it as you can see on the picture i uploaded.
CJ LTD
A CROWN
375 FOR 9CT GOLD
WHAT LOOKS LIKE A SHIELD OR ANIMAL HEAD
AND THEN A LETTER THAT LOOKS LIKE A P but im not sure!
even if its modern i would just like to know :)