description is too vague and we do not have an image of the jewelry marks which makes the hallmark determination that much harder.
There are a lot of lions & big cats, many crowns and too many anchor marks on jewelry and metals. Provenance does play a part, and although you mention your father's aunt came to Canada from Ireland in the late 1870s suggesting the ring is British made, it's not altogether conclusive.
The LEOPARD HEAD is a UK - LONDON Town mark (Uncrowned Leopard Head) - ca 1822 - Present. Many people get the lion and leopard mark confused.
The "anchor" and the "crown" symbols also have many, many variations and as complex as they appear simple.
Then we have Pseudo-British Hallmarks to be considered and eliminated from the equation and I'm afraid without an image or a more detailed description, this cannot be done.
