I found on-line an interesting article "The .455 Webley & Scott Pistol" (American Rifleman 1964) which has a chart which details both Government Contracts and Private sales deliveries by month/year/serial number. This pistol (serial number 3800) was 1 of 1919 (serial numbers 3691-5609) delivered to the Royal Navy in December 1914. It served through most of WWI.