The basic plot is this, a British tech firm is converting an old country house into a research and development centre, where they intend to create a better recording medium than magnetic tape (they basically end up describing recording mediums in use NOW as what they're trying to achieve) in a last ditch attempt to prevent the Japanese from swamping the UK electronics market (and this film being made in the early 70s, they say this in the most racist way possible).
Unfortunately though, it turns out that there is a ghost in the house, or more specifically in one room of it. After multiple people see if, including finding research that said haunting's been going on for years, the RnD guys decide to put all of their fancy equipment to use trying to find a cause of the haunting.
Despite the sometimes jarring levels of racism and sexism on display (the one woman in the movie, a computer expert who turns out to be the only one who knows what's going on, is treated like an idiot even after her saying that there was a ghost is proven right), the film is an interesting take on the haunted house genre. Good way to kill 90 minutes, and has one of the horrible, in a good way, endings I've ever seen in a horror film in ages...
Can be seen on Youtube, and I think it's in the public domain at this point,