You have a Webley RIC model MP. The Webley RIC was originally made for the Royal Irish Constabulary, and the name R.I.C. stuck even though this revolver was sold to dozensof different police forces as well as civilian sales.
The Webley RIC was produced in various models for about 60 years, from the 1870s to the 1930s. RIC models included: #1, #2, #3, 1882, 1883, and the MP. MP stood for Metropolitan Police and is the only Webley to carry the handcuff logo that you described. Manufacture of the MP model started in the early 1880s. I don't know of a source to determine date of manufacture by serial number. Dating some models of Webley revolvers is not an exact science.
Some police forces continued to use the MP model well into the 20th century; it was the issue revolver for the London Metropolitan Police until 1911 and even later for some Aussie police forces. Webley could have continued making them as long as there were sales for it.
Some webley revolvers can be dated by the trademark stamped on the revolver. Webley merged with Scott in late 1897 and the company name changed accordingly. "Webley and Son" and "P. Webley and Son" revolvers are generally considered to be antique by the CFC, while "Webley and Scott" trademarked revolvers are not. You could call the CFC and ask to talk to a firearms tech for more specific info on antique staus.
Elwood Epps can probably get the Fiocchi ammo if it's available. DO NOT use the Fiocchi .455 ammo in the .450 RIC, even though it may fit in the chamber it is much higher pressure than .450 revolver ammo. You can use .455 MKII brass (made by Hornady) loaded to .450 levels if you reload.
Value depends on condition and antique staus. An antique in excellent condition is worth as much as $1000 - $1200. If it's not antique it's worth $200-$300 at best.