Silver ring, London hallmark, maker?

[Vantlicht]

This silver ring with an agate stone has a London hallmark if I am correct. But the who maked it? Somebody who knows it?

[silvermakersmarks]

Yes, it's a London hallmark with the date letter t for 1974. There are no published references for makers' / sponsors' marks so you may not find out who SAB or C+I are.

Phil