DIAMOND RING HALLMARK HELP! i bought a ring......

by Lucy
(Liverpool)

second hand recently and i was wondering if anyone could help me date it. the hallmarks include:
GA
A SET OF SCALES
375
AND A ROSE.

i have uploaded a picture of it as zoomed in as i can get it to help you see for yourself in case i have misinterpreted any of the symbols, i have read what the scale means on a couple of questions but all the people say it has a number on the scales but my one doesn't, but it's badly rubbed from wearing, so it may have had a number there originally! even if it's not old, i would love to know anything about it, that the hallmarks can tell :)