I can imagine the Brindley & Foster, whose stoplist I looked up just now, was a very nice instrument. One B&F, I'm impressed with, is the one at Freemason Hall, Edinburgh. Though it is smaller, it still gives one a good idea of the tonal concept.
As to the positioning of the Mander, this most certainly can have a major effect on musical delivery. When considering an odd-shaped room, one should imagine sound waves moving throughout the room. While doing so, he/she should ask the question: "what would get in the way of soundwaves?", or, "what's going to prevent the congregation or audience from hearing as much of the instrument as possible?"
One idea that comes to mind is to start out by finding a spot in the Cathedral where you can see as much of the space as possible in any direction, thereby establishing a possible site for the organ. Also, take into consideration any possible acoustical interruptions in the vaulting and ceiling, bearing in mind that, ideally, you want the pipework to be placed as high up as practical, since sound carries better when its source is elevated.
As to the positioning of the Mander, this most certainly can have a major effect on musical delivery. When considering an odd-shaped room, one should imagine sound waves moving throughout the room. While doing so, he/she should ask the question: "what would get in the way of soundwaves?", or, "what's going to prevent the congregation or audience from hearing as much of the instrument as possible?"
One idea that comes to mind is to start out by finding a spot in the Cathedral where you can see as much of the space as possible in any direction, thereby establishing a possible site for the organ. Also, take into consideration any possible acoustical interruptions in the vaulting and ceiling, bearing in mind that, ideally, you want the pipework to be placed as high up as practical, since sound carries better when its source is elevated.