Very nice, don’t know the reference but it looks to be an early forerunner of their Hercules horizontal padbar. They made many changes as it evolved over the years but yours has what looks the same type of 6 lever mech and keys as used in the Battleship padlocks.
The two keys marked Chubb are originals, the other is just a copy. Chubb were always strict on this, their genuine issue blanks were marked (often with a star) to prevent a copied duplicate key from being passed off as an original.
Here’s two recent Battleship blanks for comparison:

Hopefully someone will have an old catalogue brochure or come up more info for you,dates, reference number etc.