Salford Cathedral - using your loaf and not relying on plans

I was recently appointed to write a Statement of Significance for the Cathedral House, which is part of the Roman Catholic Salford Cathedral. This is one of those cases which demonstrates that in the absence of documentary information and original plans, you have to be a bit of a building detective and (yes I admit it) a bit of a nerd, drawing on previous experiences of similar building types and wider knowledge of architecture (in this case nineteeth century architects) in order to draw out the relative significance. I am afraid there is simply no substitute for really detailed inspection and experience. It won't do just to say that a building is Grade II* and ipso facto it has to be very special and that is its significance. Some things may not be what they seem.