the ring is 18ct gold, assayed in Birmingham in the UK. When the anchor stamp, which is the city mark appears sideways, in most cases, it means the metal is gold and not silver.
The date letter mark (a in lower case) will tell you the date, however you also have to examine the shield, or cartouche around the date letter. This is very important, it is just as important as the date letter.
As I do not have the benefit of a photograph, you will be able to work the date yourself by doing a little bit of detective work with the information you will find in the following link.
Click on Birmingham Date Letters and Maker's Marks and in the top right hand corner, you will see the Birmingham Date Letter Chart. Click in there and you can then compare the letters (and the shields) on your ring with the dates in the chart.
