Is the dungeon fully sound proofed so I am free to scream and bellow and make ridiculously loud noises?
No. If you like making very loud screaming and/or bellowing noises it's best you do that in your own home.
LDH has been running successfully, without causing nuisance, since its opening in 2006. This is because our hirers are sensible and discrete and are careful that their behavior does not to cause offence or concern to others.
It is impossible to soundproof a building to completely eliminate noise and disturbance to others in a city as densely populated as London. If a dungeon claims you can make as much noise as you like it's just inconsiderate of others or it is in a very isolated (difficult to reach; not in a town or city) or it must be very stuffy with extremely limited ventilation.
Screaming and shouting can cause anxiety and concern in others... they probably do not understand the intricacies of your edge play and are certainly not interested in hearing it. They have not given their consent to be involved in your drama and therefore it is rude and unethical to involve them in it.
So please keep levels of expression of pleasure and pain to a reasonable level.
What is reasonable? Well imagine making that noise in your own home, would you feel ok about that? What if others hear the noise? Is it frightening? Is it unpleasant? Is it very loud? The answers to these questions will help to make a judgment of "reasonable" and "unreasonable".