Hi,
A friend of mine had the same problem. He made a steel frame out of 50mm thick wall square tube That went into a foundation of cement that he poured under the floor boards. The frame was anchored inside the wall to the main structural wooden beamed in a corner . Then he re clad the wall so you could not see it safe was bolted to the steel frame work. Had to get police approval for it. By the time he finished with it to get it out you would have to pull the house down.