In short Frederick T Baker patented a system of eccentric sequential cams and pushrods to cock the locks. These were not (obviously) simultaneous and WR appropriated such a system. Baker fought the case and had judgement in favour but the legal costs bankrupted him. He then (apparently) retreated into the trade and died insolvent abt 1914. Crudginton(?) has some references.

FWIW I have one of his 12 bore back action side locks; sleeved and proofed for nitro. Very nice she is with her leather case and bits.

BTW the A&D(?) fore end latch may be a later adaption. I thought a Rigby style lever might be to "period" but who knows eh?