I want to know the answer to the following question:
What part of the organ is not connected or playable?
All the background I'm provided with is that "In 1982 and 1987, Harrison and Harrison enlarged the organ under the direction of the then abbey organist Simon Preston to include an additional Lower Choir Organ and a Bombarde Organ: the current instrument now has five manuals and 109 speaking stops.". Is that enough to answer the question?
Answer: no