Marking on right hand side plate. .303 2.222" / BNP 18.5 TONS PER O". Modern proof mark for .303-inch ammunition. From Birmingham Proof House. Pressure rated at 18 tonnes per square inch.
Marking on right hand side plate. DA / 91. Deactivated at London Proof House in 1991.
Marking on water jacket. DA / 86. Deactivated at Birmingham Proof House in 1986.