Identifying mark on silver bowl

I recently purchased a silver bowl. Not sure if it is pure silver or silver plated. No markings to suggest silver plating. I have spent hours on the internet trying to research the markings to no success.
On the bottom of the bowl is inscribed SHEFFIELD WARE. In between these two words is a mark that looks like a three leafed clover. In each leaf of the clover there are letters. The top leaf is a K, the leaf on the left is a B and the leaf on the right is a C. To the left as well as to the right of this symbol there is a left-facing swastika (as we know it) marking even though the Nazi swastika is right-facing I believe. I read that it is not uncommon to use this ancient symbol before Nazism came into effect. There is also a number 662 engraved.
Thank you to anyone who can tell me if this is pure silver or silver plated, and the origins of the bowl.

If it was solid silver it would be marked as such so we must assume it is silver plated. The word “Sheffield” is often used to indicate electroplate, especially in the USA. I don’t recognise the manufacturer’s mark.

Thank you very much for your response.