I believe this to be Die II stamp of 9d watermarked CofA. SG makes a note of it as substituted cliche. Not a rarity in anyway, as it priced at 100# as a pair with regular stamp Die IIB in my 2006 SG catalog, but a curious stamp I would think.

This seller on HipStamp provides very good description of this type. I guess he/she wouldn't mind free advertisement.
https://www.hipstamp.com/listing/19...94e/22402948