Help needed identiying age of key

[bearkin]

This key belongs to a door lock in my house. The lock body is made of oak, which the iron mechanism inset in the wooden block. Any ideas of the age of the key and lock would be appreciated. We have other typically 18th C metal locks with typical 18th C keys on other doors, but this keys is different and very intricate and fits a large wooden lock.

Thanks, Pete