Sheriff Warrell is recorded as a gun business in Portsmouth on the south coast of England from 1864 until circa 1886 when his son joined his business. He never applied for Freedom (this is a reference to when completing apprenticeship and applying to the Gunmakers Company [abbr.] to be an independent Master Gunmaker. The records are not clear on with whom he apprenticed, and it appears he may not have. All gun related items indicate he was exclusively in Birmingham. You gun seems to show S. Warrell as the "gun company" - the company that made the gun, while the locks just say Warrell, which could indicate that it was completed when his son joined the first and the name changed to "Warrell - Guns and Sporting Supplies", dropping the S. from the legal name of the company. Your gun would then be circa 1886, the transition time from S. Warrell - Gun Shop to Warrell-Guns and Sporting Supplies. The company was apparently sold 3-years later.
Sherriff was known as the Champion Sparrow Shot of England. He was born in 1819 in Lincolnshire. He got a late start in the gun business. His parents were pub owners. Sheriff himself owned a pub in Cambridge but his license was taken away by the Magistrates Court because of several scrapes with the law. Around 1852 he moved to Portsmouth and re-married, although there is little know about what happened to his first wife. His first day in Portsmouth he applied for a license to be a cab driver. He had a weird personality that may have included a bit of paranoia. He often posted warnings in the paper to others that he alleged were using his name in bad reproach, that they would be sued in court if they were identified.
He was a gambler, and that is where sparrow shooting came up. He bet on how many sparrows could be shot in a row -and often won. His journal says he used 1 1/2 ounce of shot and fired at 50 sparrows to record how many were hit in a row and how many were hit out of 50, a two-tier bet. He set up Pony Trotting competitions, rat killing by dogs competitions and bicycle vs. pony competitions - all of which he participated as a betting competitor. When a famous tightrope walker needed someone to carry across the rope, Sheriff Warrell was the man. There was an assassination attempt on the Queen and it was determined that Sheriff Warrell - under his pawn brokers license - sold the assassin the cartridges.
He had a pub called the Royal Naval Pub that began in 1867. His life ended of illness in 1896 on Portsea Island, Hampshire.
Since he had no proof of apprenticeship, no licensed "gun shop" and no patents in the gun industry, there are many allegations that he was a fraud. In order to make a buck, he had his name put on guns that were outsourced entirely. One specific purpose was to boost his claim of being The Greatest Sparrow Shot of England and also use that "title" to entice others to purchase the guns. One son was the only one recorded as participating in the business, even though there were 10 children. Some allege he did this to avoid a lawsuit unto himself as well as further muddy the origin and authenticity of the guns being "made" by him or his family. With no formal training in gunmaking recorded for himself or his son, and many lawsuits, confrontations and legal actions against him throughout his life, it is also alleged that he avoided using the term "Gunmaker" in order to protect himself from lawsuits for fraud. A possible scenario is that he ordered guns from the Birmingham guild, or other independent craftsman and hired an engraver through contract to put his "name" on the gun. All known examples of his guns are very good quality. First, he modeled them to win different "shoots" and second to showcase his skills to entice others to buy the very type gun he won these shoots with. In rare instances, you may find a barrel or stockmakers initials and maybe a lock makers initials in the corresponding places on the gun, which might be discernable and traceable to a known Birmingham gunmaker. Without such markings, it can only be assumed that talented Birmingham craftsman put the guns together due to the quality, style and patents used.