The Anchor is the Birmingham Assay Office and "K" is the date mark. Marie, to find out the fineness of the gold you need to know what year your K is referring too. Without actually seeing the mark it is nearly impossible to tell.
For example, the date mark K was used in Birmingham in 1808, 1859, etc. (not for just one year)
You can find out what carat gold the ring is, by looking up the birmingham date mark. If you go to this page on the web site https://www.antique-jewelry-investor.com/antique-jewelry-hallmarks.html there's a free download with all the Historic British Hallmarks and you can then check your date mark against the year.
In the UK, from 1798 to 1854, only gold assayed at 18 and 22 ct was permissible and hallmarked. In 1854, 15, 12, and 9 ct were legalized.
