Some relatives of mine live in (part of) what used to be a remote country manor house in the north of England. Even now it's remote enough not to have mains water, sewage or gas.
However, there's evidence that the house used to have gas. There's a key labelled 'gas house' there's an 1880's plan with an out-building called 'the old gas house' (the key fits) there are various old lead tubes running about some of the walls, plus a collection of rusty ironwork in one of the cellars that appear to be old gas lights.
Was small scale domestic gas production common in the that era? (I can't find any references). How would the gas be generated? Would it be 'town gas' i.e. created by heating coal to produce coke and gas. Or would it be acetenyl gas? (made by dripping water onto calcium carbide). I can find a reference to this being used in American homes in the 1900s but not in the UK
Update for clarity - The house is actually relatively small (only six beds), and the outhouse for generating gas is only about the 2 * 3 meters. So it's a lot smaller than the gas-house shown for Culzean Castle in one of the answers. The other interesting thing is that the gas house is obviously designed to be very well ventilated, but there's no sign of there ever being a flu or chimney. There's also no sign of anything that resembles a gasometer so presumably gas was generated in real-time.