Don't forget Parker-Hale used Spanish Santa barbra actions with no thumb cutout:-

Fresh ou of the box 1200 Super in 7.92mm

P-H 1100 Deluxe in 30-06

P-H 1200V in 6mm Remington

All have faint "Spain" marking on the left side of the tang. I would appear that the customer could order different bolt hand profiles.

Edit:- Notice the similar way in which the serial numbers are stamped/rollmarked on yours and the Parker-Hales.